[LeetCode] Find the Highest Altitude

Problem: There is a biker going on a road trip. The road trip consists of n + 1 points at different altitudes. The biker starts his trip on point 0 with altitude equal 0.

You are given an integer array gain of length n where gain[i] is the net gain in altitude between points i​​​​​​ and i + 1 for all (0 <= i < n). Return the highest altitude of a point.

Example:

Input: gain = [-5,1,5,0,-7]
Output: 1
Explanation: The altitudes are [0,-5,-4,1,1,-6]. The highest is 1.

Input: gain = [-4,-3,-2,-1,4,3,2]
Output: 0
Explanation: The altitudes are [0,-4,-7,-9,-10,-6,-3,-1]. The highest is 0.

Approach: The approach is simple; we just keep adding every gain in current altitude and comparing it with max altitude. Assign max altitude to current altitude if max is less than current altitude.

Implementation in C#:

    public int LargestAltitude(int[] gain)

    {

        int length = gain?.Length ?? 0;

        if (length == 0)

        {

            return 0;

        }

        int maxAlt = 0, currAlt = 0;

        for (int i = 0; i < length; ++i)

        {

            currAlt += gain[i];

            maxAlt = maxAlt < currAlt ? currAlt : maxAlt;

        }

        return maxAlt;

    }

Complexity: O(n)