[leetcode 152]最大乘积子序列

leetcode 152

思路：dp

代码：

class Solution {
public:
    int maxProduct(vector& nums) {
        int n = nums.size();
        int ans = nums[0], Max = nums[0], Min = nums[0];
        for(int i = 1; i < n; i++){
            int tmp1 = Max*nums[i], tmp2 = Min*nums[i];
            Max = max(nums[i], max(tmp1, tmp2));
            Min = min(nums[i], min(tmp1, tmp2));
            ans = max(ans, Max);
        }
        return ans;
    }
};
int main(){
    Solution s;
    int a[10005] = {0,-1,4,-4,5,-2,-1,-1,-2,-3,0,-3,0,1,-1,-4,4,6,2,3,0,-5,2,1,-4,-2,-1,3,-4,-6,0,2,2,-1,-5,1,1,5,-6,2,1,-3,-6,-6,-3,4,0,-2,0,2};
    vector v(a, a+50);
    int ans = s.maxProduct(v);
    cout<

如果还需要输出这个序列的下标：

class Solution {
public:
    int maxProduct(vector& nums) {
        int n = nums.size();
        int Max=nums[0], Min=nums[0], l = 0, r = 0, Max_l = 0, Max_r = 0, Min_l = 0, Min_r = 0, ans = nums[0];
        for(int i = 1; i < n; i++){
            int tmp1 = Max * nums[i];
            int tmp2 = Min * nums[i];
            int tmp_max_l = Max_l, tmp_max_r = Max_r;
            if(nums[i] >= tmp1 && nums[i] >= tmp2){
                Max = nums[i];
                Max_l = Max_r = i;
            }else if(tmp1 >= nums[i] && tmp1 >= tmp2){
                Max = tmp1;
                Max_r = i;
            }else{
                Max = tmp2;
                Max_l = Min_l;
                Max_r = i;
            }

            if(nums[i] <= tmp1 && nums[i] <= tmp2){
                Min = nums[i];
                Min_l = Min_r = i;
            }else if(tmp1 <= nums[i] && tmp1 <= tmp2){
                Min = tmp1;
                Min_l = tmp_max_l;
                Min_r = i;
            }else{
                Min = tmp2;
                Min_r = i;
            }

            if(ans < Max){
                ans = Max;
                l = Max_l;
                r = Max_r;
            }
        }
        cout<