[LeetCode] Find the Highest Altitude

題目：Find the Highest Altitude
難度：Easy

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 1:

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

Example 2:

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.

Constraints:

• n == gain.length
• 1 <= n <= 100
• -100 <= gain[i] <= 100

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時間複雜度：因會遍歷整個矩陣，故時間複雜度為 O(N)，N 為矩陣長度
空間複雜度：因使用的變數為常數，故空間複雜度為 O(1)

public class Solution {
    public int LargestAltitude(int[] gain) {
       int max = Int32.MinValue;
       int currentSum = 0;

        for (int i = 0; i < gain.Length; i++)
        {
            currentSum += gain[i];
            max = Math.Max(max, currentSum);
        }

       return max > 0 ? max : 0; 
    }
}