题解 | 合法IP

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

int main() {
    string str;
    getline(cin, str);
    stringstream ss(str);
    string segment;
    int count = 0;
    bool ip = true;

    while (getline(ss, segment, '.')) {
        if (segment.length() > 1 && segment[0] == '0' || segment.size() == 0 || segment[0] == '+' ) {
            ip = false;
            break;
        }
        if (segment.empty()) {
            ip = false;
            break;
        } else {
            int num = stoi(segment);
            if (num < 0 || num > 255) {
                ip = false;
                break;
            }
            count++;
        }
    }
    if (count != 4) {
        ip = false;
    }
    if (ip) {
        cout << "YES" << endl;
    } else {
        cout << "NO" << endl;
    }

    return 0;
}
// 64 位输出请用 printf("%lld")