题解 | 字符串中找出连续最长的数字串

#include <bits/stdc++.h>
using namespace std;

class Solution {
public:
    string solve(string str) {
        string maxNum = "";     // 最长数字串
        string curNum = "";     // 当前数字串
        
        for (char c : str) {
            if (isdigit(c)) {
                curNum += c;
                // 更新最长数字串
                if (curNum.length() > maxNum.length()) {
                    maxNum = curNum;
                }
            } else {
                curNum = "";    // 重置当前数字串
            }
        }
        
        return maxNum;
    }
};

int main() {
    string str;
    getline(cin, str);
    
    Solution solution;
    cout << solution.solve(str) << endl;
    
    return 0;
}

import java.util.*;

public class Main {
    static class Solution {
        public String solve(String str) {
            String maxNum = "";     // 最长数字串
            StringBuilder curNum = new StringBuilder();    // 当前数字串
            
            for (char c : str.toCharArray()) {
                if (Character.isDigit(c)) {
                    curNum.append(c);
                    // 更新最长数字串
                    if (curNum.length() > maxNum.length()) {
                        maxNum = curNum.toString();
                    }
                } else {
                    curNum = new StringBuilder();    // 重置当前数字串
                }
            }
            
            return maxNum;
        }
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        
        Solution solution = new Solution();
        System.out.println(solution.solve(str));
        
        sc.close();
    }
}

class Solution:
    def solve(self, s):
        max_num = ""    # 最长数字串
        cur_num = ""    # 当前数字串
        
        for c in s:
            if c.isdigit():
                cur_num += c
                # 更新最长数字串
                if len(cur_num) > len(max_num):
                    max_num = cur_num
            else:
                cur_num = ""    # 重置当前数字串
        
        return max_num

# 读取输入
s = input()
solution = Solution()
print(solution.solve(s))