用ac的代码对照了N组数据了都一样一交就wa?

#include<iostream>
#include<algorithm>
const int N = 10000;
using namespace std;
int h[N],baby[N][N],b[N],ans = 0;
void bfs(int xx){
    if(xx>4)return;
    int x = h[xx];
        if(x==1){ 
            ans+=baby[xx][1];
            return;
        }
        int idx = 0;
        int ba[N];
        for(int i = 1;i<=x;i++)ba[i] = baby[xx][i];
        sort(ba+1,ba+x+1,greater<int>());
        for(int i = 1;i<=x;i++){
            if(!idx)b[idx++] = ba[i];
            else {
                b[idx++] = ba[i];
                sort(b,b+2);
                ans+=b[0];
                b[0] =b[1] - b[0];
                if(b[0]==0)idx-=2;
                else idx--;
            }
        }if(idx) ans+=b[0];
}
int main(){
    for(int i = 1; i <= 4;i++)cin>>h[i];
    for(int i = 1;i <= 4;i++)
       for (int j = 1; j <= h[i]; j ++ )
            cin>>baby[i][j];
    for(int i = 1; i <= 4;i++)bfs(i);
    cout<<ans<<endl;
    return 0;
}