题目描述：

LeetCode 780. Reaching Points

A move consists of taking a point (x, y) and transforming it to either (x, x+y) or (x+y, y).

Given a starting point (sx, sy) and a target point (tx, ty), return True if and only if a sequence of moves exists to transform the point (sx, sy) to (tx, ty). Otherwise, return False.

Examples:
Input: sx = 1, sy = 1, tx = 3, ty = 5
Output: True
Explanation:
One series of moves that transforms the starting point to the target is:
(1, 1) -> (1, 2)
(1, 2) -> (3, 2)
(3, 2) -> (3, 5)

Input: sx = 1, sy = 1, tx = 2, ty = 2
Output: False

Input: sx = 1, sy = 1, tx = 1, ty = 1
Output: True

Note:

• sx, sy, tx, ty will all be integers in the range [1, 10^9].

题目大意：

从点(x, y)出发经过一次移动可以到达(x + y, y)或者(x, x + y)

给定点(sx, sy)与(tx, ty)，判断(sx, sy)是否可以经过若干次上述移动到达(tx, ty)

解题思路：

循环取余数

类似于辗转相除法（欧几里得算法）

Python代码：

class Solution(object):
    def reachingPoints(self, sx, sy, tx, ty):
        """
        :type sx: int
        :type sy: int
        :type tx: int
        :type ty: int
        :rtype: bool
        """
        while sx < tx and sy < ty:
            if tx > ty: tx %= ty
            else: ty %= tx
        if sx == tx: return (ty - sy) % sx == 0
        if sy == ty: return (tx - sx) % sy == 0
        return False

 

本文链接：http://bookshadow.com/weblog/2018/02/16/leetcode-reaching-points/
请尊重作者的劳动成果，转载请注明出处！书影博客保留对文章的所有权利。

如果您喜欢这篇博文，欢迎您捐赠书影博客： ，查看支付宝二维码