求乘积最大组

长度为n的整形数组,找出其中任意n-1个乘积最大的那一组,只能用乘法,不可以用除法。要求对算法时间复杂度和空间复杂度进行分析。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <limits.h>


int ret1Index(const int myArray[], const int n)
//返回1个不包含在n-1个因子乘积最大组合中的因子下标
{
    int negNum = 0;//负数个数
    for (int i = 0; i < n; i++)
    {
        if (myArray[i] < 0)
        {
            negNum++;
        }
    }
    int index = -1;
    switch(negNum % 2)
    {
        case 0:
            {
                int myNum = INT_MAX;
                for (int i = 1; i < n; i++)
                {
                    if (myArray[i] >= 0 && myArray[i] <= myNum)
                    {
                        index = i;
                        myNum = myArray[i];
                    }
                }
                return index;
            }
        case 1:
            {
                int myNum = 0;
                for (int i = 0; i < n; i++)
                {
                    if (myArray[i] < 0 && abs(myArray[i]) > abs(myNum))
                    {
                        index = i;
                        myNum = myArray[i];
                    }
                }
                return index;
            }
        default:
            {
                return index;
            }
    }
}

void main()
{
    const int n=6;//数组长度
    const int myArray[n] = {-3,-2 , -1, 0, 2, 3};
    int retId = -1;
    long multiply = 1;
    retId = ret1Index(myArray,n);
    if (-1 == retId)
    {
        printf("There must be some errors in your array!
");
    }
    else
    {
        //输出乘积最大组合
        for (int i = 0; i < n; i++)
        {
            if (i != retId)
            {
                multiply *= myArray[i]; 
                printf("%d ",myArray[i]);
            }
        }
        //输出最大乘积
        printf("
%ld
",multiply);

    }
    system("pause");
    return;
}

时间复杂度为n,空间复杂度为常数C。

原文地址:https://www.cnblogs.com/alpha19881007/p/20130905_byalpha19881007.html