ACM算法题

字符串最后一个单词长度

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import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner st = new Scanner(System.in);
        String cs = st.nextLine();
        String[] word = cs.split(" ");
        System.out.println(word[word.length - 1].length());
    }
}

计算某字符出现次数

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine().toLowerCase();
        String word = in.nextLine().toLowerCase();
        System.out.println(str.length() - str.replaceAll(word, "").length());
    }
}

*明明的随机数

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        TreeSet<Integer> set = new TreeSet<>();
        for(int i = 0; i < num; i++){
            set.add(scanner.nextInt());
        }
        Iterator iterator = set.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
    }
}

字符串分隔

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            String str = in.nextLine();
            split(str);
        }
    }
    public static void split(String s){
        while(s.length() >= 8){
            System.out.println(s.substring(0,8));
            s = s.substring(8);
        }
        if(s.length() < 8 && s.length() > 0){
            s += "00000000";
            System.out.println(s.substring(0,8));
        }
    }
}

*进制转换

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import java.util.Scanner;
import java.io.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextLine()){
            String s = scanner.nextLine();
            System.out.println(Integer.parseInt(s.substring(2, s.length()), 16));
        }
    }
}

质数因子

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public class Main{
    public static void main(String[] args) {
        // 处理输入
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            // 获取需要求解的值
            int target = sc.nextInt();
            int y = 2;// 因子从2开始算
            while(target != 1){ // 短除法，除到目标值为1为止
                if(target % y == 0) // 能能够整除2
                {
                    System.out.print(y+" ");
                    target /= y;
                }else{// 更新y的值
                    if(y > target / y) y = target;//如果剩余值为质数
                    else y++;  //y值增加1
                }
            }
        }
    }
}

取近似值

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import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double num = in.nextDouble();
        System.out.println((int) (num + 0.5));
    }
}

*合并表记录

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
      Scanner scanner = new Scanner(System.in);
      int tableSize = scanner.nextInt();
      Map<Integer, Integer> table = new HashMap<>(tableSize);
      for (int i = 0; i < tableSize; i++) {
          int key = scanner.nextInt();
          int value = scanner.nextInt();
          if (table.containsKey(key)) {
              table.put(key, table.get(key) + value);
          } else {
              table.put(key, value);
          }
      }
       for (Integer key : table.keySet()) {
          System.out.println( key + " " + table.get(key));
      }
    }
}

提取不重复的整数

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import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            // 使用HashSet来判断是否是不重复的
            HashSet<Integer> hs = new HashSet<>();
            int target = sc.nextInt();// 获取代求解的值
            while(target != 0){ // 求解每位上面的整数
                int temp = target % 10;
                if(hs.add(temp)) // 如果能加入，就是说明没有重复
                    System.out.print(temp);
                target /= 10;// 除10能去掉最右边的数字
            }
            System.out.println();
        }
    }
}

*字符个数统计

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        HashSet<Character> set = new HashSet<>();
        for(int i = 0; i < str.length(); i++){
            set.add(str.charAt(i));
        }
        System.out.println(set.size());
    }
}

购物单

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import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextLine()) {
            int money = sc.nextInt();
            int m = sc.nextInt();
            sc.nextLine();
            money /= 10;
            int[][] prices = new int[m+1][3];
            int[][] weights = new int[m+1][3];
            for (int i = 1; i <= m; i++) {
                int a = sc.nextInt();
                int b = sc.nextInt();
                int c = sc.nextInt();
                a /= 10;//price
                b = b * a;//weight
                if (c == 0) {
                    // 主件
                    prices[i][0] = a;
                    weights[i][0] = b;
                } else if (prices[c][1] == 0) {
                    // 附件1
                    prices[c][1] = a;
                    weights[c][1] = b;
                } else {
                    // 附件2
                    prices[c][2] = a;
                    weights[c][2] = b;
                }
                sc.nextLine();
            }
            int[][] dp = new int[m+1][money+1];
            for (int i = 1; i <= m; i++) {
                for(int j = 1; j <= money; j++) {
                    int a = prices[i][0];
                    int b = weights[i][0];
                    int c = prices[i][1];
                    int d = weights[i][1];
                    int e = prices[i][2];
                    int f = weights[i][2];

                    dp[i][j] = j - a >= 0 ? Math.max(dp[i-1][j], dp[i-1][j-a] + b) : dp[i-1][j];
                    dp[i][j] = j-a-c >= 0 ? Math.max(dp[i][j], dp[i-1][j-a-c] + b + d):dp[i][j];
                    dp[i][j] = j-a-e >= 0 ? Math.max(dp[i][j], dp[i-1][j-a-e] + b + f):dp[i][j];
                    dp[i][j] = j-a-c-e >= 0 ? Math.max(dp[i][j], dp[i-1][j-a-c-e] + b +d + f):dp[i][j];
                }
            }

            System.out.println(dp[m][money] * 10);
        }
    }
}

*坐标移动

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import java.util.*;
import java.io.*;

public class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        String[] in = bf.readLine().split(";");
        int x = 0;
        int y = 0;
        for(String s : in){
            // 不满足题目给定坐标规则
            if(!s.matches("[WASD][0-9]{1,2}")){
                continue;
            }
            int val = Integer.valueOf(s.substring(1));
            switch(s.charAt(0)){
                case 'W':
                    y += val;
                    break;
                case 'S':
                    y -= val;
                    break;
                case 'A':
                    x -= val;
                    break;
                case 'D':
                    x += val;
                    break;
            }
        }
        System.out.println(x+","+y);
    }
}

*密码验证合格程序

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import java.util.*;
import java.util.regex.*;
public class Main{
    public static void main(String[] arg){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String str = sc.next();
            if(str.length() <= 8){
                System.out.println("NG");
                continue;
            }
            if(getMatch(str)){
                System.out.println("NG");
                continue;
            }
            if(getString(str, 0, 3)){
                System.out.println("NG");
                continue;
            }
            System.out.println("OK");
        }
    }
    // 校验是否有重复子串
    private static boolean getString(String str, int l, int r) {
        if (r >= str.length()) {
            return false;
        }
        if (str.substring(r).contains(str.substring(l, r))) {
            return true;
        } else {
            return getString(str,l+1,r+1);
        }
    }
    // 检查是否满足正则
    private static boolean getMatch(String str){
        int count = 0;
        Pattern p1 = Pattern.compile("[A-Z]");
        if(p1.matcher(str).find()){
            count++;
        }
        Pattern p2 = Pattern.compile("[a-z]");
        if(p2.matcher(str).find()){
            count++;
        }
        Pattern p3 = Pattern.compile("[0-9]");
        if(p3.matcher(str).find()){
            count++;
        }
        Pattern p4 = Pattern.compile("[^a-zA-Z0-9]");
        if(p4.matcher(str).find()){
            count++;
        }
        if(count >= 3){
            return false;
        }else{
            return true;
        }
    }
}

合唱队

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import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            int n = sc.nextInt();
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = sc.nextInt();
            }

            int[] left = new int[n]; //存储每个数左边小于其的数的个数
            int[] right = new int[n];//存储每个数右边小于其的数的个数
            left[0] = arr[0];
            right[n - 1] = arr[n-1];
            int num[] =new  int [n];//记录以i为终点的从左向右和从右向走的子序列元素个数
            int index = 1;//记录当前子序列的长度
            for(int i=1;i<n;i++){
                if(arr[i]>left[index-1]){
                    //直接放在尾部
                    num[i] = index;//i左侧元素个数
                    left[index++] = arr[i];//更新递增序列
                }else {
                    //找到当前元素应该放在的位置
                    int low = 0,high = index-1;
                    while(low < high){
                        int mid = (low+high)/2;
                        if(left[mid] <arr[i])
                            low = mid + 1;
                        else
                            high = mid;
                    }
                    //将所属位置替换为当前元素
                    left[low] = arr[i];
                    num[i] = low;//当前位置i的左侧元素个数
                }
            }
            index = 1;
            for(int i=n-2;i>=0;i--){
                if(arr[i]>right[index-1]){
                     num[i] += index;
                     right[index++] = arr[i];
                }else {
                    int low = 0,high = index-1;
                    while(low < high){
                        int mid = (high+low)/2;
                        if(right[mid]<arr[i])
                            low = mid+1;
                        else
                            high = mid;
                    }
                    right[low] = arr[i];
                    num[i]+=low;
                }
            }
            int max = 1;
            for (int number: num )
                max = Math.max(max,number);
            // max+1为最大的k
            System.out.println(n - max);
        }
    }
}

*字符串排序

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import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String original = "";
        while ((original = br.readLine()) != null) {

            // 遍历字符串并存入TreeMap中
            TreeMap<Character, StringBuilder> map = new TreeMap<>();
            for (char c: original.toCharArray()) {
                if ('a' <= c && c <= 'z') {
                    if (!map.containsKey(c)) {
                        map.put(c, new StringBuilder());
                    }
                    map.get(c).append(c);
                } else if ('A' <= c && c <= 'Z') {
                    char k = (char)(c - 'A' + 'a');
                    if (!map.containsKey(k)) {
                        map.put(k, new StringBuilder());
                    }
                    map.get(k).append(c);
                }
            }

            // 将已排序好的字母部分合并
            StringBuilder sb = new StringBuilder();
            for (Map.Entry<Character, StringBuilder> entry: map.entrySet()) {
                sb.append(entry.getValue());
            }

            // 重新遍历字符串以插入非字母的字符
            for (int i = 0; i < original.length(); i++) {
                char other = original.charAt(i);
                if ('a' <= other && other <= 'z') {
                    continue;
                } else if ('A' <= other && other <= 'Z') {
                    continue;
                } else {
                    sb.insert(i, other);
                }
            }
            System.out.println(sb.toString());
        }
        br.close();
    }
}

*删除字符串中出现次数最少的字符

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import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        Map<Character,Integer> map = new HashMap<>();
        while(in.hasNextLine()){
            int min = Integer.MAX_VALUE;
            String str = in.nextLine();
            int len = str.length();
            for(int i = 0; i < len; i++){
                char ch = str.charAt(i);
                if(!map.containsKey(ch)){
                    map.put(ch,1);
                    min = Math.min(min,1);
                }else{
                    int num = map.get(ch) + 1;
                    map.put(ch,num);
                    if(!map.containsValue(min)){//最小值增大的情况
                        min = num;
                    }
                }
            }
            for(int i = 0; i < len; i++){
                if(min != map.get(str.charAt(i))){
                    System.out.print(str.charAt(i));
                }
            }
            System.out.println();
            map.clear();
        }
    }
}

*整数和IP地址间的转换

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import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String s = sc.next();
            if(s.contains(".")){
                System.out.println(ip2num(s));
            }else{
                System.out.println(num2ip(Long.parseLong(s)));
            }
        }
    }

    public static long ip2num(String ip){
        String[] iip = ip.split("\\.");
        StringBuilder sb = new StringBuilder();
        for(int i=0; i<4; i++){
            int num = Integer.parseInt(iip[i]);  // 拆分
            String num2 = Integer.toBinaryString(num);  //转换为二进制
            while(num2.length()<8){
                num2 = "0" + num2;  // 拼接
            }
            sb.append(num2);
        }
        return Long.parseLong(sb.toString(), 2);  // 转化为10进制
    }

    public static String num2ip(long num){
        String num2 = Long.toBinaryString(num);  //转换为2进制
        while(num2.length()<32){
            num2 = "0" + num2;
        }
        String[] ans = new String[4];
        for(int i=0; i<4; i++){
            String s = num2.substring(8*i, 8*i+8);  //拆分
            s = Integer.toString(Integer.parseInt(s, 2));  //转化为10进制
            ans[i] = s;
        }
        return String.join(".", ans);  //拼接
    }
}

*输入整型数组和排序标识，对其元素按照升序或降序进行排序

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            int num = in.nextInt();
            Integer[] arr = new Integer[num];
            for(int i = 0; i < num; i++){
                arr[i] = in.nextInt();
            }
            int flag = in.nextInt();
            if(flag == 0){
                Arrays.sort(arr, new Comparator<Integer>(){
                    public int compare(Integer o1, Integer o2){
                        return o1 - o2;
                    }
                });
            }else if(flag == 1){
                Arrays.sort(arr,new Comparator<Integer>(){
                    public int compare(Integer o1,Integer o2){
                        return o2-o1;
                    }
                });
            }

            for(Integer n : arr){
                System.out.print(n + " ");
            }
            System.out.println();
        }
    }
}

*字符逆序

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        StringBuilder sb = new StringBuilder(str);
        System.out.println(sb.reverse());
    }
}

*查找兄弟单词

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            String[] str = in.nextLine().split(" ");
            Integer num = Integer.parseInt(str[0]);
            String x = str[str.length - 2];
            Integer k = Integer.parseInt(str[str.length - 1]);
            List<String> list = new ArrayList<>();

            for(int i = 1; i <= num; i++){
                if(isBro(x, str[i])){
                    list.add(str[i]);
                }
            }
            int size = list.size();
            System.out.println(size);

            if(size >= k){
                Collections.sort(list);
                System.out.println(list.get(k - 1));
            }
        }
    }
    public static boolean isBro(String x, String n){
        if(x.length() != n.length() || n.equals(x)){
            return false;
        }
        char[] cs = x.toCharArray();
        char[] key = n.toCharArray();
        Arrays.sort(cs);
        Arrays.sort(key);
        return new String(cs).equals(new String(key));
    }
}

*成绩排序

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        HashMap<Integer, String> map = new HashMap<>();
        while(in.hasNext()){
            int num = Integer.parseInt(in.nextLine());
            int flag = Integer.parseInt(in.nextLine());
            int[][] score = new int[num][2];
            for(int i = 0; i < num; i++){
                String[] nameAndScore = in.nextLine().split(" ");
                score[i][0] = i;
                score[i][1] = Integer.parseInt(nameAndScore[1]);
                map.put(i, nameAndScore[0]);
            }

            Arrays.sort(score, (o1, o2) -> {
                if(flag == 0){
                    return o2[1] - o1[1];
                }else{
                    return o1[1] - o2[1];
                }
            });

            for(int i = 0; i < num; i++){
                System.out.println(map.get(score[i][0]) + " " + score[i][1]);
            }
        }

    }
}

*称砝码

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        HashSet<Integer> set = new HashSet<>();
        while (in.hasNext()) { // 注意 while 处理多个 case
            set.add(0);
            int n = in.nextInt();
            int[] w = new int[n];
            int[] nums = new int[n];
            for(int i = 0; i < n; i++){
                w[i] = in.nextInt();
            }
            for(int i = 0; i < n; i++){
                nums[i] = in.nextInt();
            }

            for(int i = 0; i < n; i++){
                List<Integer> list = new ArrayList<>(set);
                for(int j = 1; j <= nums[i]; j++){
                    for(int k = 0; k < list.size(); k++){
                        set.add(list.get(k) + w[i] * j);
                    }
                }
            }
            System.out.println(set.size());
        }
    }
}

*求最小公倍数

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import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int a = in.nextInt();
        int b = in.nextInt();
        int c = a;
        System.out.println(gcd(a, b, c));
    }
    public static int gcd(int a, int b, int c){
        if(a % b == 0){
            return a;
        }
        return gcd(a + c, b, c);
    }
}

*素数伴侣

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();

        List<Integer> evenList = new ArrayList<>();
        List<Integer> oddList = new ArrayList<>();
        for(int i = 0; i < num; i++){
            int j = in.nextInt();
            if(isEven(j)){
                evenList.add(j);
            }else{
                oddList.add(j);
            }   
        }

        int size = evenList.size();
        int count = 0;

        int[] evensMatch = new int[size];

        for(Integer odd : oddList){
            int[] used = new int[size];
            if(find(odd, evenList, used, evensMatch)){
                count++;
            }
        }
        System.out.println(count);
        in.close();
    }

    public static boolean isEven(int n){
        if(n % 2 == 0){
            return true;
        }
        return false;
    }

    public static boolean isPrime(int n){
        if(n <= 1){
            return false;
        }else{
            for(int i = 2; i < n; i++){
                if(n % i == 0){
                    return false;
                }
            }
        }
        return true;
    }

    public static boolean find(int odd, List<Integer> evens, int[] used, int[] evenMatch){
        for(int i = 0; i < evens.size(); i++){
            if(isPrime(odd + evens.get(i)) && used[i] == 0){
                used[i] = 1;
                if(evenMatch[i] == 0 || find(evenMatch[i], evens, used,evenMatch)){
                    evenMatch[i] = odd;
                    return true;
                }
            }
        }
        return false;
    }
}

*查找组成一个偶数最接近的两个素数

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int left = n / 2;
        int right = n / 2;
        while(left > 2 && right < n - 2){
            if(isPrime(left) && isPrime(right) && n == left + right){
                break;
            }else{
                left--;
                right++;
            }
        }
        System.out.println(left);
        System.out.println(right);
    }

    public static boolean isPrime(int n){
        if(n <= 2){
            return false;
        }
        for(int i = 2; i < n; i++){
            if(n % i == 0){
                return false;
            }
        }
        return true;
    }
}

*数据分类处理

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import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            int num = in.nextInt();
            String[] arr = new String[num];
            for(int i = 0; i < num; i++){
                arr[i] = String.valueOf(in.nextInt());
            }

            int Rnum = in.nextInt();
            Set<Integer> set = new TreeSet<>();
            for(int i = 0; i < Rnum; i++){
                set.add(in.nextInt());
            }

            StringBuilder res = new StringBuilder();
            int count = 0;
            for(int i : set){
                int j = 0;
                Map<Integer, String> map = new TreeMap<>();

                for(String str : arr){
                    if(str.contains(String.valueOf(i))){
                        map.put(j, str);
                    }
                    j++;
                }
                if(!map.isEmpty()){
                    if(count > 0){
                        res.append(" ");
                    }
                    res.append(i).append(" ").append(map.size());
                    count += 2;
                    for(Map.Entry<Integer, String> entry : map.entrySet()){
                        count += 2;
                        res.append(" ").append(entry.getKey()).append(" ").append(entry.getValue());
                    }
                }
            }
            if(count > 0){
                StringBuilder result = new StringBuilder();
                result.append(count).append(" ").append(res.toString());
                System.out.println(result.toString());
            }
        }
    }
}

汽水瓶

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import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextInt()){
            int bottle = scanner.nextInt();
            if(bottle == 0){
                break;
            }
            System.out.println(bottle / 2);
        }


    }
}