Java(javac 1.8) 解法, 执行用时: 132ms, 内存消耗: 14548K, 提交时间: 2019-11-29 10:05:11

import java.util.*;
import java.io.*;

public class Main {

	final public static int COWSPERTEAM = 3;
	final public static int NUMCOWS = 12;
	final public static int NOSOL = 10000000;

	public static void main(String[] args) throws Exception {

		Scanner stdin = new Scanner(System.in);
		int[] values = new int[NUMCOWS];
		for (int i=0; i<NUMCOWS; i++)
			values[i] = stdin.nextInt();
		stdin.close();

		int[] teams = new int[NUMCOWS];
		boolean[] used = new boolean[NUMCOWS];
		int cost = recSolve(values, 0, teams, used);

		System.out.println(cost);
	}

	public static int recSolve(int[] values, int k, int[] teams, boolean[] used) {

		if (k == NUMCOWS) return eval(values, teams);

		int lowCow = 0;
		if (k > 0 && k%3 > 0) lowCow = teams[k-1]+1;
		else if (k > 0 && k%3 == 0) lowCow = teams[k-3]+1;

		int result = NOSOL;
		for (int i=lowCow; i<NUMCOWS; i++) {
			if (!used[i]) {
				teams[k] = i;
				used[i] = true;
				result = Math.min(result, recSolve(values, k+1, teams, used));
				used[i] = false;
			}
		}
		return result;
	}

	public static int eval(int[] values, int[] teams) {

		int[] scores = new int[NUMCOWS/COWSPERTEAM];
		for (int i=0; i<NUMCOWS; i++)
			scores[i/COWSPERTEAM] += values[teams[i]];

		int res = 0;
		for (int i=0; i<scores.length; i++)
			for (int j=i+1; j<scores.length; j++)
				res = Math.max(res, Math.abs(scores[i]-scores[j]));
		return res;
	}
}

C++11(clang++ 3.9) 解法, 执行用时: 15ms, 内存消耗: 596K, 提交时间: 2020-04-05 11:30:46

#include <bits/stdc++.h>
#define M int(1e9)
using namespace std;
int a[13],o[13]={0,1,1,1,2,2,2,3,3,3,4,4,4},s[5];
int main()
{
	//freopen("bteams.in","r",stdin);
	//freopen("bteams.out","w",stdout);
	for(int i=1;i<=12;i++)
	cin>>a[i];
	sort(a+1,a+13); 
	int ans=M;
	do
	{
		for(int i=1;i<=4;i++)
		s[i]=0;
		for(int i=1;i<=12;i++)
		s[o[i]]+=a[i];
		int minn=M,maxn=0;
		for(int i=1;i<=4;i++)
		{
			minn=min(minn,s[i]);
			maxn=max(maxn,s[i]);
		}
		ans=min(ans,maxn-minn);
	}while(next_permutation(o+1,o+13));
	cout<<ans;
	return 0;
 } 

C++14(g++5.4) 解法, 执行用时: 41ms, 内存消耗: 384K, 提交时间: 2020-04-06 11:45:07

#include<stdio.h>
#define fo(i,a,b) for(int i=a;i<=b;i++)
#define fd(i,a,b) for(int i=a;i>=b;i--)
#include<algorithm>
using namespace std;
int n=12,ans,a[15],bel[15],num[6],sum[6],te;
void dfs(int now){
	if (now>n){
		fo(i,1,4) sum[i]=0;
		fo(i,1,n) sum[bel[i]]+=a[i];
		sort(sum+1,sum+5);
		te=sum[4]-sum[1];
		if (te<ans) ans=te;
		return;
	}
	fo(i,1,4) if (num[i]<3){
		num[i]++;
		bel[now]=i;
		dfs(now+1);
		num[i]--;
	}
}
int main(){
	ans=0x3fffffff;
	fo(i,1,n) scanf("%d",&a[i]);
	dfs(1);
	printf("%d\n",ans);
}