CodeForces 102A - flody

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最新推荐文章于 2020-08-30 17:59:19 发布

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I - Clothes

Time Limit:2000MS Memory Limit:262144KB 64bit IO Format:%I64d & %I64u

Submit Status Practice CodeForces 102A

Description

A little boy Gerald entered a clothes shop and found out something very unpleasant: not all clothes turns out to match. For example, Gerald noticed that he looks rather ridiculous in a smoking suit and a baseball cap.

Overall the shop sells n clothing items, and exactly m pairs of clothing items match. Each item has its price, represented by an integer number of rubles. Gerald wants to buy three clothing items so that they matched each other. Besides, he wants to spend as little money as possible. Find the least possible sum he can spend.

Input

The first input file line contains integers n and m — the total number of clothing items in the shop and the total number of matching pairs of clothing items ( $\text{[math]}$ ).

Next line contains n integers a_i (1 ≤ a_i ≤ 10⁶) — the prices of the clothing items in rubles.

Next m lines each contain a pair of space-separated integers u_i and v_i (1 ≤ u_i, v_i ≤ n, u_i ≠ v_i). Each such pair of numbers means that theu_i-th and the v_i-th clothing items match each other. It is guaranteed that in each pair u_i and v_i are distinct and all the unordered pairs (u_i, v_i)are different.

Output

Print the only number — the least possible sum in rubles that Gerald will have to pay in the shop. If the shop has no three clothing items that would match each other, print "-1" (without the quotes).

Sample Input

Input

Output

Input

Output

-1

Input

Output

-1

Hint

In the first test there only are three pieces of clothing and they all match each other. Thus, there is only one way — to buy the 3 pieces of clothing; in this case he spends 6 roubles.

The second test only has three pieces of clothing as well, yet Gerald can't buy them because the first piece of clothing does not match the third one. Thus, there are no three matching pieces of clothing. The answer is -1.

In the third example there are 4 pieces of clothing, but Gerald can't buy any 3 of them simultaneously. The answer is -1.

题目意思：

某人要选3件衣服，条件是：选的3件衣服要能两两搭配（也就是两两节点是有边相连的map[i][j] = map[j][i] = 1）

而每个件衣服有自己的价格（也就是每个节点有自己权值）,要求选出这样的衣服，使得总的价格最小，要是没有满足条件的，那就输出-1

分析：其实酒店hi选出最小的环，可以用flody、、、

代码：

#include <iostream>
#include <string.h>
#include <algorithm>
#include <math.h>
#include <stdio.h>

using namespace std;

#define INF 1 << 29
int g[150][150];
int price[150];
int n, m;
int ans;
int flody () {
	ans = INF;
	for(int i = 1;i <= n;i ++)
		for(int j = i + 1;j <= n;j ++)
			for(int k = j + 1;k <= n;k ++)
				if(g[i][j] && g[j][k] && g[k][i]) {
					ans = min(ans, price[i] + price[j] + price[k]);	
				}
				return ans;
}
int main(){
	int u, v;
	while (scanf("%d%d",&n, &m) != EOF) {
		memset(g, 0, sizeof(g));
		memset(price, 0, sizeof(price));
		for (int  i = 1; i <= n; i ++)
			scanf("%d", &price[i]);
		for (int i = 0; i < m; i ++) {
			scanf("%d%d", &u, &v);
			g[u][v] = g[v][u] = 1;
		}
		//flody();
		if(flody() == INF) printf("-1\n");
		else printf("%d\n", flody());
	}
	return 0;
}