Crazy Binary String

解题思路

把1记为1，把0记为-1，然后求前缀和，前缀和相等的就说明中间的01数一样。只要记录前缀和数值出现的位置即可更新出答案。

代码如下

#include 
    
     #define INF 0x3f3f3f3fusing namespace std;typedef long long ll;const int N = 100005;int l[N << 1];int sum[N];int main(){    int n;    scanf("%d%*c", &n);    int ans1 = 0;    int a, b;    a = b = 0;    for(int i = 1; i <= n; i ++){        char ch = getchar();        if(ch == '0'){            ++a;            sum[i] = sum[i - 1] - 1;        }        else if(ch == '1'){            ++b;            sum[i] = sum[i - 1] + 1;        }        if(l[sum[i] + N] || sum[i] == 0)            ans1 = max(ans1, i - l[sum[i] + N]);        else            l[sum[i] + N] = i;    }    cout << ans1 << " " << 2 * min(a, b) << endl;    return 0;}