交换两个数组的元素使之总和的差值最小

题目描述：

有两个数组a,b，大小都为n,数组元素的值任意整型数，无序；

要求：通过交换a,b中的元素，使数组a元素的和与数组b元素的和之间的差最小。

#include "stdafx.h"

#include <math.h>
#include <time.h>
#include <stdlib.h>

void print_arr(int a[], int b[], int n)
{
	printf("a: ");
	for (int i=0;i<n;i++)
	{
		printf("%d ", a[i]);
	}
	printf("\n");
	printf("b: ");
	for (int i=0;i<n;i++)
	{
		printf("%d ", b[i]);
	}
	printf("\n");
	printf("\n");
}

bool swap_min(int a[], int b[], int n)
{
	printf("before swap:\n");
	print_arr(a, b, n);

	// 初始化差值
	int sum_a=0;
	int sum_b=0;
	for (int k=0;k<n;k++)
	{
		sum_a += a[k];
		sum_b += b[k];
	}

	int delta_init = abs(sum_a - sum_b);

	for (int i=0;i<n;i++)
	{
		/*if (delta_init == 0) // 优化处理
		{
			break;
		}*/

		int sum_a=0;
		int sum_b=0;
		for (int k=0;k<n;k++)
		{
			sum_a += a[k];
			sum_b += b[k];
		}

		// 假设交换，差值是否更小
		bool bswp = false;
		int jpos = 0;
		for (int j=0;j<n;j++)
		{
			int sum_atemp = sum_a-a[i]+b[j];
			int sum_btemp = sum_b-b[j]+a[i];
			int delta_temp = abs(sum_atemp-sum_btemp);
			if (delta_temp < delta_init)
			{
				delta_init = delta_temp;
				jpos = j;
				bswp =true;
			}
		}

		// 假设成功，执行交换元素
		if (bswp)
		{
			int tmp = a[i];
			a[i] = b[jpos];
			b[jpos] = tmp;
		}
	}

	printf("after swap:\n");
	print_arr(a,b,n);

	return true;
}

int _tmain(int argc, _TCHAR* argv[])
{
	int a[5] = {0, 0, 0, 0, 9};//1,2,3,4,5
	int b[5] = {1, 2, 5, 4, 3};//6,7,8,9,100

	int c[] = {1,2,3,4,5};
	int d[] = {6,7,8,9,100};

	int e[]={1,2,3,4,5};
	int f[]={10,20,30,40,50};
	////////////////////////
	swap_min(a, b, 5);
	swap_min(c, d, 5);
	swap_min(e, f, 5);

	errno_t err;
	unsigned int number;
	err = rand_s(&number);  

	int m[100];
	int n[100];
	srand( (unsigned)time(NULL)); //生成种子
	for (int i=0;i<100;i++)
	{
		m[i]=rand()%100;
		n[i]=abs(rand()%200-100);
	}
	swap_min(m, n, 10);
	////////////////////////
	getchar();

	return 0;
}