package openlock

import "fmt"

func openLock(deadends []string, target string) int {
	deads := make(map[string]int)
	for _, v := range deadends {
		deads[v]++
	}
	queue := make([]string, 0, 0)
	queue = append(queue, "0000")
	step := 0
	for len(queue) != 0 {
		size := len(queue)
		for i := 0; i < size; i++ {
			// 出队
			top := queue[0]
			queue = queue[1:]
			if _, dead := deads[top]; dead {
				continue
			}
			if top == target {
				return step
			}
			fmt.Println(top)
			deads[top]++
			for j := 0; j < 4; j++ {
				nodeUp := clickUp(top, j)
				nodeDown := clickDown(top, j)
				queue = append(queue, nodeUp, nodeDown)
			}
		}
		step++
	}
	return -1
}

func clickUp(code string, idx int) string {
	decodes := []byte(code)
	ch := decodes[idx]
	if ch == '9' {
		decodes[idx] = '0'
		return string(decodes)
	}
	ch++
	decodes[idx] = ch
	return string(decodes)
}

func clickDown(code string, idx int) string {
	decodes := []byte(code)
	ch := decodes[idx]
	if ch == '0' {
		decodes[idx] = '9'
		return string(decodes)
	}
	ch--
	decodes[idx] = ch
	return string(decodes)
}