题解 | 字符串操作

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

int main()
{
    int n,m;
    string s = "";
    cin >> n >> m;
    cin >> s;
    while(m--)
    {
        int l,r;
        char c1,c2;
        cin >> l >> r;
        cin >> c1 >> c2;
        for(int i = l; i <= r; i++)
        {
            if(s[i-1] == c1)
            {
                s[i-1] = c2;
            }
        }
    }
    cout << s;
    return 0;
}