Problem - 1186C - Codeforces

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define syncfalse ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
const int N = 1e6+5;
char a[N], b[N];
int pre[N][2];
int main(){
    syncfalse
    #ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
    #endif
    cin>>a+1>>b+1;
    int n = strlen(a+1), m = strlen(b+1);
    int num0 = 0, num1 = 0;
    for (int i = 1; i <= m; ++i){
        if (b[i]=='0')num0++;
        else num1++;
    }
    for (int i = 1; i <= n; ++i){
        pre[i][0]+=pre[i-1][0];
        pre[i][1]+=pre[i-1][1];
        if (a[i]=='1')pre[i][1]++;
        else pre[i][0]++;
    }
    int l = 1;
    int ans = 0;
    for (int r = m; r <= n; ++r, ++l){
        int now1 = pre[r][1]-pre[l-1][1];
        int tem = abs(now1-num1);
        if (tem%2==0)ans++;
    }
    cout << ans << "\n";

    return 0;
}