3909. Compare Sums of Bitonic Parts

You are given a bitonic array nums of length n.

Split the array into two parts:

• Ascending part: from index 0 to the peak element (inclusive).
• Descending part: from the peak element to index n - 1 (inclusive).

The peak element belongs to both parts.

Return:

• 0 if the sum of the ascending part is greater.
• 1 if the sum of the descending part is greater.
• -1 if both sums are equal.

Notes:

• A bitonic array is an array that is strictly increasing up to a single peak element and then strictly decreasing.
• An array is said to be strictly increasing if each element is strictly greater than its previous one (if exists).
• An array is said to be strictly decreasing if each element is strictly smaller than its previous one (if exists).

class Solution {
public:
    int compareBitonicSums(vector<int>& nums) {
        int idx = max_element(begin(nums), end(nums)) - begin(nums);
        long long sum = 0;
        for(int i = 0; i < nums.size(); i++) {
            if(i != idx) sum = (sum + (i < idx ? 1 : -1) * nums[i]);
        }
        return sum > 0 ? 0 : sum < 0 ? 1 : -1;
    }
};