bzoj1800 [Ahoi2009]fly 飞行棋 暴力枚举

啊啊啊我要疯了！！！tmd这么水的题目我居然因为一个地方打错调了半个小时，我是不是傻逼啊。

#include<cstdio>#include<algorithm>#include<cstring>#define fo(i,a,b) for(int i=a;i<=b;i++)#define fd(i,a,b) for(int i=a;i>=b;i--)using namespace std;const int N=25;typedef long long ll;int n,m;int ans;int vis[N];int a[N];ll mp[N][N];inline void solve(){    static int b[5];    int tot=0;    fo(i,1,20)if (vis[i])b[++tot]=i;    if(tot!=4)return;    if (mp[b[1]][b[2]]==mp[b[3]][b[4]]&&mp[b[2]][b[3]]==mp[b[1]][b[4]])ans++;}inline void dfs(int x,int dep){    if (dep==4||x==n+1)    {        solve();        return;    }    dfs(x+1,dep);    vis[x]=1;    dfs(x+1,dep+1);    vis[x]=0;}int main(){    scanf("%d",&n);    ll sum=0;    fo(i,1,n)scanf("%d",&a[i]),sum+=a[i];    fo(i,1,n)    {        fo(j,i+1,n)        {            ll tmp=0;            fo(k,i,j-1)tmp+=a[k];            mp[i][j]=min(tmp,sum-tmp);            mp[j][i]=mp[i][j];        }    }    /*fo(i,1,n)    {        fo(j,1,n)printf("%lld ",mp[i][j]);        printf("\n");    }*/    dfs(1,0);    printf("%d\n",ans);    return 0;}