leetcode-go/easy/496.next-greater-element-i.go

func nextGreaterElement(findNums []int, nums []int) []int {
	stack := make([]int, 0) // Keep a decease stack
	next := make(map[int]int)
	for _, i := range nums {
		for l := len(stack); l != 0 && stack[l-1] < i; l = len(stack) {
			top := stack[l-1]
			stack = stack[:l-1]
			next[top] = i
		}
		stack = append(stack, i)
	}
	res := make([]int, len(findNums))
	for i := range res {
		if val, ok := next[findNums[i]]; ok {
			res[i] = val
		} else {
			res[i] = -1
		}
	}
	return res
}