int maxSub(int A[], int left, int right){
if(left > right) return INT_MIN;
if(left == right) return A[left];
int mid = (left + right) / 2;
int currSum = 0, leftMax = INT_MIN, rightMax = INT_MIN;
for(int i = mid - 1; i >= left; i--){
currSum += A[i];
leftMax = max(leftMax, currSum);
}
for(int i = mid + 1, currSum = 0; i <= right; i++){
currSum += A[i];
rightMax = max(rightMax, currSum);
}
int midMax = A[mid] + max(leftMax, 0) + max(rightMax, 0);
return max(midMax, max(maxSub(A, left, mid - 1), maxSub(A, mid + 1, right)));
}
int maxSub(vector<int>& nums, int l, int r) {
if(l == r) return nums[l];
int m = (l + r) / 2;
int leftMax = maxSub(nums, l, m);
int rightMax = maxSub(nums, m + 1, r);
int mMax = nums[m];
int sum = mMax;
for(int i = m - 1; i >= l; --i)
{
sum += nums[i];
mMax = sum > mMax ? sum : mMax;
}
sum = mMax;
for(int i = m + 1; i <= r; ++i)
{
sum += nums[i];
mMax = sum > mMax ? sum : mMax;
}
return max(leftMax, rightMax, mMax);
}
int maxSubArray(int A[], int n) {
// Note: The Solution object is instantiated only once and is reused by each test case.
return maxSub(A, 0, n - 1);
}
int maxSubArray(vector<int>& nums) {
return maxSub(nums, 0, nums.size() - 1);
}