152. Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product.

For example, given the array [2,3,-2,4],
the contiguous subarray [2,3] has the largest product = 6.

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这个问题如果该数组中有偶数个负数，没有0，那么就是全部数相乘最大。如果有奇数个负数，没有0，那么最大的子集可能是去掉最左边那个负数，或者最右边那个负数。也就是比较两种情况那个子集乘积大取哪个。

 Forward*=nums[i];        Back*=nums[numsSize-1-i];        Larger=(Forward>Back)? Forward:Back;        GlobalMax=(GlobalMax>Larger)?GlobalMax:Larger;  

如果中间有0，那么重新计数。

  if(Forward==0) Forward=1;        if(Back==0) Back=1;

完整程序：

int maxProduct(int* nums, int numsSize) {    int Forward=1;      int Back=1;    int GlobalMax=nums[0];    int Larger=1;    for(int i=0;i<numsSize;i++){          Forward*=nums[i];        Back*=nums[numsSize-1-i];        Larger=(Forward>Back)? Forward:Back;        GlobalMax=(GlobalMax>Larger)?GlobalMax:Larger;          if(Forward==0) Forward=1;        if(Back==0) Back=1;    };      return GlobalMax;  }