CF920C Swap Adjacent Elements greedy

I do not know the spade, water it wants ~

code: 

#include <bits/stdc++.h>
#define N 300004 
#define setIO(s) freopen(s".in","r",stdin) 
using namespace std;  
char S[N]; 
int a[N],s[N];  
int main() 
{
    // setIO("input"); 
    int i,j,n,flag=0; 
    scanf("%d",&n); 
    for(i=1;i<=n;++i) scanf("%d",&a[i]);     
    scanf("%s",S+1);  
    for(i=1;i<n;++i) 
    {
        if(S[i]=='0') s[i]=0; else s[i]=1; 
        s[i]+=s[i-1];
    }   
    for(i=1;i<=n;++i) 
    {
        if(a[i]>i) 
        {
            int dis=a[i]-i;    
            if(s[a[i]-1]-s[i-1]!=dis) flag=1; 
        }
        if(a[i]<i) 
        {
            int dis=i-a[i]; 
            if(s[i-1]-s[a[i]-1]!=dis) flag=1;  
        }
    }  
    if(flag) printf("NO\n"); 
    else printf("YES\n"); 
    return 0;  
}