関連ワード:  peak element in an array leetcode    maximum element in an array leetcode    find peak element in an array leetcode    peak element in mountain array leetcode    peak element in 2d array leetcode    second maximum element in an array leetcode    maximum and minimum element in an array leetcode    maximum and minimum element in an array leetcode problem    find peak element in mountain array leetcode    find minimum and maximum element in an array leetcode