题解 | 倒着输出整数

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

void solve() {
    string s;
    cin >> s;
    
    // 处理负号
    if (s[0] == '-') {
        cout << "-";
        s = s.substr(1);
    }
    
    // 反转字符串
    reverse(s.begin(), s.end());
    
    // 去除前导零
    string result;
    bool found = false;
    for (char c : s) {
        if (!found && c == '0') continue;
        found = true;
        result += c;
    }
    
    // 处理全零的情况
    if (result.empty()) result = "0";
    
    cout << result << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int t = 1;
    while (t--) {
        solve();
    }
    return 0;
}

import java.util.*;

public class Main {
    static void solve(Scanner sc) {
        String s = sc.next();
        
        // 处理负号
        if (s.charAt(0) == '-') {
            System.out.print("-");
            s = s.substring(1);
        }
        
        // 反转字符串
        StringBuilder sb = new StringBuilder(s);
        sb.reverse();
        s = sb.toString();
        
        // 去除前导零
        StringBuilder result = new StringBuilder();
        boolean found = false;
        for (char c : s.toCharArray()) {
            if (!found && c == '0') continue;
            found = true;
            result.append(c);
        }
        
        // 处理全零的情况
        if (result.length() == 0) result.append("0");
        
        System.out.println(result);
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t = 1;
        while (t-- > 0) {
            solve(sc);
        }
        sc.close();
    }
}

def solve():
    s = input()
    
    # 处理负号
    if s[0] == '-':
        print('-', end='')
        s = s[1:]
    
    # 反转字符串并去除前导零
    s = s[::-1]
    result = s.lstrip('0')
    
    # 处理全零的情况
    if not result:
        result = '0'
    
    print(result)

def main():
    t = 1
    while t:
        solve()
        t -= 1

if __name__ == "__main__":
    main()