题解 | 字符串操作

#include <iostream>
using namespace std;

int main() {
    int n, m;
    int c1, c2;
    char b1, b2;
    string a;
    cin >> n >> m;
    cin >> a;
    for (int i = 0; i < m; i++) {
        cin >> c1 >> c2 >> b1 >> b2;
        for (int j = c1 -1; j <= c2 -1; j++) {
            if (j >= 0 && j <n) {
                if (a[j] == b1) a[j] = b2;
            }
        }
    }
    cout << a << endl;
}
// 64 位输出请用 printf("%lld")