POJ-1659 Frogs' Neighborhood---Havel-Hakimi定理

题目链接：

https://vjudge.net/problem/POJ-1659

题目大意：

给定度数列，判断是否可以建图

思路：

Havel-Hakimi定理

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<set>
#include<sstream>
#include<functional>
using namespace std;
typedef long long ll;
const int maxn = 1e2 + 10;
const int INF = 1e9 + 7;
int T, n, m, cases;
int Map[maxn][maxn];
struct node
{
    int x, id;
    bool operator<(const node & a)const
    {
        return x > a.x;
    }
}a[maxn];

int main()
{
    cin >> T;
    while(T--)
    {
        cin >> n;
        for(int i = 0; i < n; i++)
        {
            cin >> a[i].x;
            a[i].id = i;
        }
        memset(Map, 0, sizeof(Map));
        bool flag = 1;
        for(int i = 0; i < n; i++)
        {
            sort(a + i, a + n);
            if(a[i].x >= n - i)
            {
                flag = 0;
                break;
            }
            for(int j = 1 + i; j <= a[i].x + i; j++)
            {
                a[j].x--;
                if(a[j].x < 0)flag = 0;
                Map[a[i].id][a[j].id] = Map[a[j].id][a[i].id] = 1;
            }
        }
        if(flag)
        {
            puts("YES");
            for(int i = 0; i < n; i++)
            {
                printf("%d", Map[i][0]);
                for(int j = 1; j < n; j++)
                {
                    printf(" %d", Map[i][j]);
                }
                puts("");
            }
        }
        else puts("NO");
        if(T)cout<<endl;
    }
    return 0;
}