package main

import "fmt"

// FindPeak finds the peak element in the array
func findPeak(arr []int) int {
	n := len(arr)

	// first or last element is peak element
	if n == 1 {
		return 0
	}
	if arr[0] >= arr[1] {
		return 0
	}
	if arr[n-1] >= arr[n-2] {
		return n - 1
	}

	// check for ever other element
	for i := 1; i < n-1; i++ {
		// check if the neighbors are smaller
		if arr[i] >= arr[i-1] && arr[i] >= arr[i+1] {
			return i
		}
	}
	return -1 // inficating no peak found
}

func main() {
	arr := []int{1, 3, 20, 4, 1, 21, 0}
	fmt.Println("Index of a peak point is", findPeak(arr))
}