A. A Compatible Pair
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Nian is a monster which lives deep in the oceans. Once a year, it shows up on the land, devouring livestock and even people. In order to keep the monster away, people fill their villages with red colour, light, and cracking noise, all of which frighten the monster out of coming.

Little Tommy has n lanterns and Big Banban has m lanterns. Tommy‘s lanterns have brightness a1, a2, ..., an, and Banban‘s have brightness b1, b2, ..., bm respectively.

Tommy intends to hide one of his lanterns, then Banban picks one of Tommy‘s non-hidden lanterns and one of his own lanterns to form a pair. The pair‘s brightness will be the product of the brightness of two lanterns.

Tommy wants to make the product as small as possible, while Banban tries to make it as large as possible.

You are asked to find the brightness of the chosen pair if both of them choose optimally.
Input

The first line contains two space-separated integers n and m (2 ≤ n, m ≤ 50).

The second line contains n space-separated integers a1, a2, ..., an.

The third line contains m space-separated integers b1, b2, ..., bm.

All the integers range from  - 109 to 109.
Output

Print a single integer — the brightness of the chosen pair.
Examples
input

2 2
20 18
2 14

output

252

input

5 3
-1 0 1 2 3
-1 0 1

output

2

Note

In the first example, Tommy will hide 20 and Banban will choose 18 from Tommy and 14 from himself.

In the second example, Tommy will hide 3 and Banban will choose 2 from Tommy and 1 from himself.

題意：Banban將會從Tommy的序列中取走一個數，和自己序列的一個數組成乘積最大。但是Tommy希望Banban最終組成的數盡可能小，而且它將會提前從自己序列中取走一個數以此來達到目的。

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<algorithm>
#define INF 1e18
typedef long long ll;
using namespace std;
ll n, m, a[110], b[110];
int main()
{
    while(cin >> n >> m){
        for(int i = 0; i < n; i++){
            cin >> a[i];
        }
        for(int i = 0; i < m; i++){
            cin >> b[i];
        }
        ll maxn = -INF, flag;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < m; j++){
                if(a[i]*b[j] > maxn){
                    maxn = a[i]*b[j];
                    flag=i;
                }
            }
        }
        maxn=-INF;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < m; j++){
                if(i==flag)
                    continue;
                if(a[i]*b[j] >maxn){
                    maxn = a[i]*b[j];
                }
            }
        }
        cout << maxn << endl;
    }
    return 0;
}

Codeforces - 934A A Compatible Pair(暴力)