题解 | 字符逆序

#include <iostream>
using namespace std;

int main() {
    string str;
    while (getline(cin, str)) {
        size_t start = str.find_first_not_of(" \t\n\r");
        if (start == string::npos) {
            cout << "" << endl;
        } else {
            size_t end = str.find_last_not_of(" \t\n\r");
            str.substr(start, end - start + 1);
        }

        for (int i = str.size() - 1; i >= 0; i--)
            cout << str[i];

    }
}
// 64 位输出请用 printf("%lld")