[Leetcode] Find Peak Element

一时失言乱红尘 2021-11-10 12:40 190阅读 0赞

![828820-20190519225525716-1782479573.png][]

找出一個大於兩邊的頂點，可以把nums\[-1\] ,nums\[n\] 都視為負無限

因為我用 int.minvalue來代表 num\[-1\] 及 num\[n\]的值

所以leetcode的test case 有一個測試是 \[-2147483648\] ，用來坑minvalue的

public class Solution
        {
            public int FindPeakElement(int[] nums)
            {
                int leftNeighber = int.MinValue;
                int rightNeighber = int.MinValue;
                int current = int.MinValue;
                int result = -1;
                for(int i = 0; i < nums.Length; i++)
                {
                    current = nums[i];
    
                    if(i -1 >=0 && i -1 <= nums.Length - 1)
                    {
                        leftNeighber = nums[i - 1];
                    }
                    else
                    {
                        leftNeighber = int.MinValue;
                    }
    
                    if (i + 1 >= 0 && i + 1 <= nums.Length - 1)
                    {
                        leftNeighber = nums[i + 1];
                    }
                    else
                    {
                        rightNeighber = int.MinValue;
                    }
    
                    if ((leftNeighber == int.MinValue || current > leftNeighber) && 
                        (rightNeighber == int.MinValue || current > rightNeighber))
                    {
                        result = i;
                        break;
                    }
    
                    
                }
                return result;
            }
        }

![828820-20190519225859041-1288123778.png][]

转载于:https://www.cnblogs.com/seako/p/10891377.html

[828820-20190519225525716-1782479573.png]: /images/20211109/ee550a47a50c49adad68f54976fe30b4.png
[828820-20190519225859041-1288123778.png]: /images/20211109/842b6ec62add4cd09723e2387259bde9.png