152. Maximum Product Subarray（重要！）

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

​​[2,3,-2,4]​​,the contiguous subarray ​​[2,3]​​ has the largest product = ​​6​​.

class Solution {
public:
  int maxProduct(vector<int>& nums) {
    //vector<int>maxSub(nums);
    int localMax = nums[0];
    int localMin = nums[0];
    int gmax = localMax;
    for (int i = 1; i < nums.size(); i++){
      int tmp = localMax;
      localMax = max(max(localMax*nums[i], nums[i]), localMin*nums[i]);
      localMin = min(min(localMin*nums[i], nums[i]), tmp*nums[i]);

      if (localMax > gmax){
        gmax = localMax;
      }
    }
    return gmax;
  }
};