1868. 一下子Accepted不了吧 - 并查集

 

 

 

 

#pragma GCC optimize("-Ofast","-funroll-all-loops")
#include<bits/stdc++.h>
//#define int long long
using namespace std;
const int N=1e6+10;
int n,f[N],q; char str[N];
int find(int x){return x==f[x]?x:f[x]=find(f[x]);}
signed main(){
    cin>>n>>q; scanf("%s",str+1);
    for(int i=1;i<=n+1;i++)    f[i]=i;
    for(int i=1,l,r,res;i<=q;i++){
        scanf("%d %d",&l,&r);    res=0;
        int now=find(l);
        while(now<=r){
            if(str[now]=='A')    res++;
            now=f[now]=find(now+1);
        }
        printf("%d\n",res);
    }
    return 0;
}