nowcoder 天气预报

https://ac.nowcoder.com/acm/problem/235096

双指针，就按这个形式写了

#include <iostream>
#include <map>
#include <cstring>
#include <algorithm>
using namespace std ;
 const int  N=1e6+10;
 #define int long long
 
 int n,a,b;
 int A ;
 char s[N];
 
 signed main(){
 	int l,r;
 	cin>>n>>a>>b;
 	cin>>(s+1);	 n=strlen(s+1) ;
 	int c1=0,c2=0,ans=0 ;
 	l=1,r=1;
 	
  	while(r<=n){
  		if(s[r]=='0') c1++; else c2++;
  		
 		while(l<=r &&(c1>=a) && (c2>=b)){
 			ans+= n-r+1;
 			if(s[l]=='0') c1--; else c2--;
 			l++;
 		}
 		r++;
 	}
 	if(a+b==0) ans++;
 	cout<<ans<<endl;
 }