第十三天：数据结构的锅

突然想起 LeetCode，这是一个我不喜欢的地方，不过既然想去就去刷一刷。刷了几题觉得有时候就是很偏见的的玩意，比如奖字符串中的元音反转，也就是 hello 会变成 holle，也就玩玩。

准备结束刷新到 https://leetcode.com/problems/flatten-nested-list-iterator/ ，然后默默在编辑器写后运行，跑过自己本地的 Testcase，但是贴上去竟然出错。代码如下：

var NestedIterator = function(nestedList) {
  this.nestedList = nestedList;
};

NestedIterator.prototype.flatten = function(arr, ret) {
  if(!ret) ret = [];
  for(var i = 0, j = arr.length; i < j; i++) {
    Array.isArray(arr[i]) ? this.flatten(arr[i], ret) : ret.push(arr[i]);
  }
  return ret;
};

NestedIterator.prototype.hasNext = function() {
  var tmp = this.nestedList[0];
  while(tmp && tmp.toString() === '') {
    this.nestedList.shift();
    tmp = this.nestedList[0];
  }
  return this.nestedList.length;
};

NestedIterator.prototype.next = function() {
  var ret = this.nestedList.shift();
    if(Array.isArray(ret)) {
    [].unshift.apply(this.nestedList, this.flatten(ret));
    ret = this.nestedList.shift();
  }
  return ret;
};

var i = new NestedIterator([[1,1],2,[1,1]])
var a = [];

while (i.hasNext()) a.push(i.next());
console.log(a);

运行起来是没问题的，但是要求并！不！是！一！个！纯！数！组！所以呵呵哒，总的来说，就是一个奇怪的古老程序员喜欢的复杂的数据结构，所以实现起来也真是：垃圾结果导致垃圾代码。

重要的话已经吐了，再见～

丑的一起看：

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * function NestedInteger() {
 *
 *     Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     @return {boolean}
 *     this.isInteger = function() {
 *         ...
 *     };
 *
 *     Return the single integer that this NestedInteger holds, if it holds a single integer
 *     Return null if this NestedInteger holds a nested list
 *     @return {integer}
 *     this.getInteger = function() {
 *         ...
 *     };
 *
 *     Return the nested list that this NestedInteger holds, if it holds a nested list
 *     Return null if this NestedInteger holds a single integer
 *     @return {NestedInteger[]}
 *     this.getList = function() {
 *         ...
 *     };
 * };
 */
/**
 * @constructor
 * @param {NestedInteger[]} nestedList
 */
var NestedIterator = function(nestedList) {
    this.nestedList = nestedList;
    this.tmp = [];
};

NestedIterator.prototype.flatten = function(arr, ret) {
    if(!ret) ret = [];
    arr = arr.getList ? arr.getList() : arr;
    for(var i = 0, j = arr.length; i < j; i++) {
        Array.isArray(arr[i].getList()) ? this.flatten(arr[i].getList(), ret) : ret.push(arr[i].getInteger());
    }
    return ret;
};

/**
 * @this NestedIterator
 * @returns {boolean}
 */
NestedIterator.prototype.hasNext = function() {
    var tmp = this.nestedList[0];
    while(tmp && tmp.getList() && this.flatten(tmp.getList()).toString() === '') {
        this.nestedList.shift();
        tmp = this.nestedList[0];
    }
    return this.nestedList.length || this.tmp.length;
};

/**
 * @this NestedIterator
 * @returns {integer}
 */
NestedIterator.prototype.next = function() {
    if(this.tmp.length) return this.tmp.shift();

    var ret = this.nestedList.shift();

    if(ret.isInteger()) {
        ret = ret.getInteger(); 
    } else {
        [].unshift.apply(this.tmp, this.flatten(ret));
        ret = this.tmp.shift();
    }

    return ret;
};

/**
 * Your NestedIterator will be called like this:
 * var i = new NestedIterator(nestedList), a = [];
 * while (i.hasNext()) a.push(i.next());
*/

sofish / learn-js

第十三天：数据结构的锅 #15