Leetcode刷题笔记(c++)

注重0和负数的影响

class Solution {
public:
    int maxProduct(vector& nums) {
        int n=nums.size();
        int out=nums[0];
        int neg_first=1,neg_pro=1;
        int neg_n=0;
        for(int i:nums){
            if(i>0){
                neg_pro*=i;
                out=max(out,neg_pro);
            }else if(i==0){
                neg_pro=1;
                neg_n=0;
                out=max(out,0);
            }else{
                neg_n++;
                if(neg_n==1){
                    neg_first=neg_pro*i;
                    neg_pro=1;
                    out=max(out,neg_first);
                }else{
                    if(neg_n%2==0){
                        neg_pro=neg_pro*i*neg_first;
                        out=max(out,neg_pro);
                    }
                    else{
                        neg_pro=neg_pro*i/neg_first;
                        out=max(out,neg_pro);
                    } 
                }            
            }
        }
        return out;
    }
};