1732. Find the Highest Altitude

1. Description

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.

2. Example

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.

3. Constraints

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

4. Solutions

Prefix Sum

n = gain.size()
Time complexity: O(n)
Space complexity: O(1)

class Solution {
public:
    int largestAltitude(const vector<int> &gain) {
        int altitude = 0, largest_altitude = 0;
        for (int i = 0; i < gain.size(); ++i) {
            altitude += gain[i];
            largest_altitude = max(largest_altitude, altitude);
        }
        return largest_altitude;
    }
};