René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"777.在lr字符串中交换相邻字符","articleBody":"[原题地址](https://leetcode-cn.com/problems/swap-adjacent-in-lr-string/)\r\n\r\n\u003e 在一个由 'L' , 'R' 和 'X' 三个字符组成的字符串（例如\"RXXLRXRXL\"）中进行移动操作。一次移动操作指用一个\"LX\"替换 一个\"XL\"，或者用一个\"XR\"替换一个\"RX\"。现给定起始字符串start和结束字符串end，请编写代码，当且仅当存在一系列移动 操作使得start可以转换成end时， 返回True。\r\n\r\n### 题解\r\n题目只需要求从start能否通过 'XL' =\u003e 'LX', 'RX' =\u003e 'XR' 操作到end, 观察到'XL'只能替换成'LX', 'RX'只能替换成'XR', 也就是'L'只能向左移动，'R'只能向右移动，且'L'和'R'不能交换。\r\n所以要判断start 能否到达end，只需要满足以下两个条件即可\r\n1. start去掉'X'后的字符串 等于 end去掉'X'后的字符串\r\n2. 如果满足1，那么对每个满足start[p1] === end[p2] 的位置\r\n   1. 如果start[p1] === 'L', 那么 p1 必须 \u003e= p2, 因为 L 只能向左移动\r\n   2. 同理，如果end[p1] === 'R', 那么 p1 必须 \u003c= p2, 因为 R 只能向右移动\r\n\r\n### 代码实现\r\n```js\r\n/**\r\n * @param {string} start\r\n * @param {string} en\r\n * @return {boolean}\r\n */\r\nvar canTransform = function(start, end) {\r\n  let startCopy = start\r\n  let endCopy = end\r\n  if (startCopy.replace(/X/g, '') !== endCopy.replace(/X/g, '')) {\r\n    console.log('here')\r\n    return false\r\n  }\r\n  let p1 = p2 = 0;\r\n  while(p1 \u003c start.length \u0026\u0026 p2 \u003c end.length) {\r\n    while(start[p1] === 'X') {\r\n      p1++\r\n    }\r\n    while(end[p2] === 'X') {\r\n      p2++\r\n    }\r\n    if (start[p1] !== end[p2]) {\r\n      return false\r\n    } else {\r\n      if ((start[p1] === 'L' \u0026\u0026 p1 \u003c p2) || (start[p1] === 'R' \u0026\u0026 p1 \u003e p2)) {\r\n        return false\r\n      }\r\n    }\r\n    p1++;\r\n    p2++;\r\n  }\r\n  return true\r\n};\r\n```","author":{"url":"https://github.com/feikerwu","@type":"Person","name":"feikerwu"},"datePublished":"2020-03-04T09:19:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/7/algorithm-camp/issues/7"}