LeetCode75——Day18

一、题目

1732. Find the Highest Altitude

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

二、题解

利用前缀和的思想解决，使用*max_element()函数可以返回vector中的最大值。

class Solution {
public:
    int largestAltitude(vector<int>& gain) {
        int n = gain.size();
        vector<int> prefixSum(n + 1,0);
        for(int i = 1;i <= n;i++){
            prefixSum[i] = prefixSum[i-1] + gain[i-1];
        }
        return *max_element(prefixSum.begin(),prefixSum.end());
    }
};