Leetcode-918 Maximum Sum Circular Subarray(环形子数组的最大和)

class Solution
{
    public:
        int maxSumCycle(vector<int>&vec, int &left, int&right)
        {
            int maxsum = INT_MIN, curMaxSum = 0;
            int minsum = INT_MAX, curMinSum = 0;
            int sum = 0;
            int begin_max = 0, begin_min = 0;
            int minLeft, minRight;
            for(int i = 0; i < vec.size(); i++)
            {
                sum += vec[i];
                if(curMaxSum >= 0)
                {
                    curMaxSum += vec[i];
                }
                else
                {
                    curMaxSum = vec[i];
                    begin_max = i;
                }

                if(maxsum < curMaxSum)
                {
                    maxsum = curMaxSum;
                    left = begin_max;
                    right = i;
                }
                if(curMinSum <= 0)
                {
                    curMinSum += vec[i];
                }
                else
                {
                    curMinSum = vec[i];
                    begin_min = i;
                }

                if(minsum > curMinSum)
                {
                    minsum = curMinSum;
                    minLeft = begin_min;
                    minRight = i;
                }
            }
            if(maxsum >= sum - minsum)
                return maxsum;
            else
            {
                left = minRight+1;
                right = minLeft-1;
                return sum - minsum;
            }
        }
        int maxSubarraySumCircular(vector<int>& A)
        {
            int flag = 1;
            int MIN = INT_MIN;
            for(auto d:A)
            {
                if(d>=0)
                {
                    flag = 0;
                    break;
                }    
                if(d>MIN)
                    MIN = d;
            }
            if(flag)
            {
                return MIN;
            }
            int a = 0,b = A.size()-1;
            return maxSumCycle(A,a,b);
        }
};

核心代码部分参考:https://www.cnblogs.com/TenosDoIt/p/3698246.html