82分，TLE

#include<bits/stdc++.h>
using namespace std;
struct node
{
    int a,b;
}match[10000];
int k,n;
int shizhanying=0;
int ans=0;
long long last[10000];
int score[30]={0};
int check()
{
    for(int i=1;i<=n;i++)
    {
        if(last[i]!=score[i])return 1;
    }
    return 0;
}
void dfs(int i,int d)
{
    if(i==k+1){if(check()==0){ans++;}return;}
    if((k-i+1)<(shizhanying-d))return;

    score[match[i].a]+=3;
    if(score[match[i].a]<=last[match[i].a]){dfs(i+1,d);}
    score[match[i].a]-=3;

    score[match[i].b]+=3;
    if(score[match[i].b]<=last[match[i].b]){dfs(i+1,d);}
    score[match[i].b]-=3;

    if(d<shizhanying)
    {
        score[match[i].a]+=1;
        score[match[i].b]+=1;
        if(score[match[i].a]<=last[match[i].a]&&score[match[i].b]<=last[match[i].b])
        {
            dfs(i+1,d+1);
        }
        score[match[i].a]-=1;
        score[match[i].b]-=1;
    }
}
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>last[i];
    }

    int sum=0;
    for(int i=1;i<=n;i++)
    {
        sum+=last[i];
    }
    k=n*(n-1)>>1;
    int ssr=k+(k<<1);
    shizhanying=ssr-sum;

    int tamp=1;
    for(int i=1;i<n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            match[tamp].a=i;
            match[tamp].b=j;
            tamp++;
        }
    }
    dfs(1,0);
    cout<<ans;
    return 0;
}