C++(g++ 7.5.0) 解法, 执行用时: 6ms, 内存消耗: 1052K, 提交时间: 2023-04-07 00:29:38

#include<bits/stdc++.h>

using namespace std;

int main(){
    int n;
    cin>>n;
    string s;
    cin>>s;
    s = " " + s;
    vector<int> fr(n+1);
    for(int i=1;i<=n;i++){
        fr[i] = fr[i-1] + (s[i]=='1');
    }
    int ans = 0;
    for(int i=1;i<=n/2;i++){
        int sum = fr[i+n/2-1] - fr[i-1];
        if(sum*2==fr[n]) ans++;
    }
    ans *= 2;
    cout<<ans<<endl;
}

Python3 解法, 执行用时: 109ms, 内存消耗: 7112K, 提交时间: 2022-12-25 23:59:41

n = int(input())
s = input()
cc, r = 0, n//2
ss = [int(v) for v in s]
if sum(ss) % 2 != 0:
    print(0)
else:
    sums = sum(ss) //2
    ss = ss * 2
    a = sum(ss[:r])
    if a == sums:
            cc += 1       
    for i in range(1,n):
        a += ss[i+r-1] - ss[i-1]
        if a == sums:
            cc += 1
        
    print(cc)
    

C++ 解法, 执行用时: 6ms, 内存消耗: 908K, 提交时间: 2021-11-20 23:01:18

#include<bits/stdc++.h>
using namespace std;
const int N=3e5+5;
char s[N];
int cnt[N];
int main()
{
	int n;
	cin>>n>>s+1;
	for(int i=1;s[i];i++)
	cnt[i]=cnt[i-1]+(s[i]=='1');
	int ans=0;
	if(cnt[n]&1)
	{
		puts("0");
		return 0;
	}
	for(int i=n/2+1;i<=n;i++)
	if(cnt[i]-cnt[i-n/2]==cnt[n]/2)
	ans++;
	printf("%d\n",ans*2);
}