题解 | #回文串#

#include<bits/stdc++.h>
using namespace std;
int main(){
    int len;
    int n;
    char c[200005];
    cin>>len>>n;
    for(int i = 0; i < len; i++){
        cin>>c[i];
    }
    for(int i = 0; i < n; i++){
        int type;
        int l;
        int r;
        char ch;
        cin>>type;
        if(type == 1){
            cin>>l>>r;
            if(r - l <= 2) cout<<"YES"<<endl;
            else{
                int time = 0;
                l--;
                r--;
                while(l < r){
                    if(c[l] != c[r]){
                        time++;
                    }
                    l++;
                    r--;
                    if(time > 1) break;
                }
                if(time > 1) cout<<"NO"<<endl;
                else cout<<"YES"<<endl;
            }
        }else{
            cin>>l>>r>>ch;
            l--;
            while(l < r){
                c[l++] = ch;
            }
        }
    }
    return 0;
}