https://leetcode.com/problems/product-of-array-except-self/description/
解题思路：
http://blog.csdn.net/wzy_1988/article/details/46916179
class Solution {
public:
vector<int> productExceptSelf(vector<int>& nums) {
vector<int> result(nums.size());
result[0] = 1;
int p = 1;
for (int i = 1; i < nums.size(); i++){
p *= nums[i-1];
result[i] = p;
}
p = 1;
for (int i = nums.size()-2; i >= 0; i--){
p *= nums[i+1];
result[i] *= p;
}
return result;
}
};
LeetCode: Product of Array Except Self
原文：http://www.cnblogs.com/yxzfscg/p/7467141.html