poj 1659【Frogs' Neighborhood】

 Havel-Hakimi定理

http://blog.sina.com.cn/s/blog_818d3d930100wdv1.html

http://hi.baidu.com/krdefndrsbbekmd/item/a7c58810f40156f8dceecab7

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

struct node
{
    int u;
    int dg;
}p[15];
int N;
int map[15][15];

bool cmp(const node& a,const node& b)
{
    return a.dg > b.dg;
}

int main()
{
   int cases;
   cin >> cases;
   while(cases --)
   {
       cin >> N;
       memset(map,0,sizeof(map));
       for(int i = 0;i < N;i ++)
       {
           cin >> p[i].dg;
           p[i].u = i;
       }

       bool flag = false;
       while(true)
       {
           sort(p,p+N,cmp);
           int t = 0;
           for(int i = 1;i <= p[0].dg;i ++)
           {
               p[i].dg -= 1;
               if(p[i].dg < 0)
               {
                   flag = true;
                   break;
               }
               map[p[0].u][p[i].u] = 1;
               map[p[i].u][p[0].u] = 1;
               t = t | p[i].dg;
           }
           if(flag)
           {
               break;
           }
           for(int i = p[0].dg + 1;i < N;i ++)
           {
               t = t | p[i].dg;
           }
           p[0].dg = 0;
           if(t == 0)
           {
               break;
           }
       }

       if(flag)
       {
           cout << "NO" << endl;
       }
       else
       {
           cout << "YES" << endl;
           for(int i = 0;i < N;i ++)
           {
               cout << map[i][0];
               for(int j = 1;j < N;j ++)
               {
                   cout << " " << map[i][j];
               }
               cout << endl;
           }
       }
        if(cases) cout << endl;
   }

   return 0;
}