题目：

题解：

type pair struct {
	x, y int
}

func canMeasureWater(jug1Capacity int, jug2Capacity int, targetCapacity int) bool {
	//剪枝
	if jug1Capacity+jug2Capacity < targetCapacity {
		return false
	}

	var (
		dfs func(x, y int) bool   // jug1有x水，jug2有y水 能否达到target
		vis = make(map[pair]bool) // 记忆化
	)

	dfs = func(x, y int) bool {
		//记忆化
		p := pair{x, y}
		if vis[p] {
			return false
		}
		vis[p] = true

		//x、y组合就是答案
		if x == targetCapacity || y == targetCapacity || x+y == targetCapacity {
			return true
		}
		//x、y分别装满、倒空
		if dfs(jug1Capacity, y) || dfs(0, y) || dfs(x, jug2Capacity) || dfs(x, 0) {
			return true
		}

		//x、y分别倒对方里
		x2y := min(x, jug2Capacity-y)
		y2x := min(y, jug1Capacity-x)
		return dfs(x-x2y, y+x2y) || dfs(x+y2x, y-y2x)
	}

	return dfs(0, 0)
}