5032. 字符串操作

#include <iostream>
#include <cstring>
using namespace std;
int n, m, l, r;
char c1, c2;
string s;

void modify(int l, int r, char x, char y){
    for(int i=l-1; i<r; i++)
        if(s[i] == x)
            s[i] = y;
}

int main(){
    cin>>n>>m>>s;
    while(m --){
        cin>>l>>r>>c1>>c2;
        modify(l, r, c1, c2);
    }
    cout<<s;
}