Today I have done leetcode's February LeetCoding Challenge with cpp.

February LeetCoding Challenge 26

Description

Maximum Absolute Sum of Any Subarray

You are given an integer array nums. The absolute sum of a subarray [numsl, numsl+1, ..., numsr-1, numsr] is abs(numsl + numsl+1 + ... + numsr-1 + numsr).

Return the maximum absolute sum of any (possibly empty) subarray of nums.

Note that abs(x) is defined as follows:

• If x is a negative integer, then abs(x) = -x.
• If x is a non-negative integer, then abs(x) = x.

Example 1:

Input: nums = [1,-3,2,3,-4]
Output: 5
Explanation: The subarray [2,3] has absolute sum = abs(2+3) = abs(5) = 5.

Example 2:

Input: nums = [2,-5,1,-4,3,-2]
Output: 8
Explanation: The subarray [-5,1,-4] has absolute sum = abs(-5+1-4) = abs(-8) = 8.

Constraints:

• 1 <= nums.length <= 105
• -104 <= nums[i] <= 104

Solution

class Solution {
public:
  int maxAbsoluteSum(vector<int>& nums) {
    int minPrefix = 100000;
    int maxPrefix = -100000;
    int prefix = 0;
    int answer = 0;
    for(auto i : nums) {
      prefix += i;
      minPrefix = min(minPrefix, prefix);
      maxPrefix = max(maxPrefix, prefix);
      answer = max(prefix - minPrefix, answer);
      answer = max(maxPrefix - prefix, answer);
      answer = max(abs(prefix), answer);
    }
    return answer;
  }
};

// Accepted
// 66/66 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 78.26 % of cpp submissions (45.1 MB)