interface.go

package law

type changeNode struct {
	change_type int
	pre         *changeNode
	list        *[]int
}

func CheckList(list []int) (int, bool) {
	return checkList(list)
}

func checkList(list []int) (val int, ok bool) {
	val, ok = 0, false
	root := BuildCheckChain()
	changers := []changer{getDiffList, getDivList, getOpenRoot}
	var bfs func(list []int) (bool, int, changeNode)
	bfs = func(list []int) (bool, int, changeNode) {
		queue := []changeNode{{list: &list}}
		for len(queue) > 0 {
			newChange := queue[0]
			ok_, v := check(root, *newChange.list)
			if ok_ {
				return ok_, v, newChange
			}
			for inx, changer := range changers {
				if len(*newChange.list) < 4 {
					continue
				}
				new_list := changer(*newChange.list)
				if new_list == nil {
					continue
				}
				change := changeNode{list: &new_list, change_type: inx + 1, pre: &newChange}
				queue = append(queue, change)
			}
			queue = queue[1:]
		}
		return false, 0, changeNode{}
	}

	ok, val, change := bfs(list)
	if !ok {
		return
	}
	ok, val = inverseOperation(&change, val)
	return
}

func BuildCheckChain() *checkNode {
	// 构建检查责任链
	nodes := []checker{checkEquivocation, checkIsometric, checkOpenRootEquivocation}
	return linkCheck(nodes...)
}

func invOperationFactor(c int) (inv invChanger) {
	// 逆操作的简单工厂
	switch c {
	case 1:
		inv = invDiff
	case 2:
		inv = invMultiplication
	case 3:
		inv = invOpenRoot
	}
	return
}