The observed PIN - my solution

The observed PIN - my solution

月光魔力鸭

2018-10-25 08:37 阅读 2913 喜欢 1 codewar 刷题 PIN组合 codewars

Alright, detective, one of our colleagues successfully observed our target person, Robby the robber. We followed him to a secret warehouse, where we assume to find all the stolen stuff. The door to this warehouse is secured by an electronic combination lock. Unfortunately our spy isn't sure about the PIN he saw, when Robby entered it.

The keypad has the following layout:

┌───┬───┬───┐
│ 1 │ 2 │ 3 │
├───┼───┼───┤
│ 4 │ 5 │ 6 │
├───┼───┼───┤
│ 7 │ 8 │ 9 │
└───┼───┼───┘
    │ 0 │
    └───┘

He noted the PIN 1357, but he also said, it is possible that each of the digits he saw could actually be another adjacent digit (horizontally or vertically, but not diagonally). E.g. instead of the 1 it could also be the 2 or 4. And instead of the 5 it could also be the 2, 4, 6 or 8.

He also mentioned, he knows this kind of locks. You can enter an unlimited amount of wrong PINs, they never finally lock the system or sound the alarm. That's why we can try out all possible (*) variations.

Can you help us to find all those variations? It would be nice to have a function, that returns an array (or a list in Java and C#) of all variations for an observed PIN with a length of 1 to 8 digits. We could name the function getPINs (get_pins in python, GetPINs in C#). But please note that all PINs, the observed one and also the results, must be strings, because of potentially leading '0's. We already prepared some test cases for you.

Detective, we count on you!


There's my solution below.

idea

1 .we got a keypad map in question 2. then got a array with map and parameters 3. and we could get max-length of result 4. rise the index ,get the results

code

function getPINs(observed) {
  // TODO: This is your job, detective!
  var map = {
    1 : [1,2,4],
    2 : [1,2,3,5],
    3 : [3,2,6],
    4 : [1,4,5,7],
    5 : [2,4,5,6,8],
    6 : [3,5,6,9],
    7 : [4,7,8],
    8 : [5,7,8,9,0],
    9 : [6,8,9],
    0 : [8,0]
  }
  function getNum(arr,index) {
    return arr.map( (item,i)=>{
      return item[index[i].start];
    }).join('');
  }
  function riseNum(index){
    let isUp = false;
    return index.reverse().map( (item,i)=> {
      let start = item.start,max = item.max;
      if(i ===0 ||isUp === true)start++;
      if(start === max){
        isUp = true;
        start = 0;
      }else{
        isUp = false;
      }
      return {start : start,max : max};
    }).reverse();
  }
  var arr = observed.split('').map( item => {
    return map[item];
  });
  var index = arr.map( item=> {
    return {start : 0,max : item.length}
  });
  var max = arr.reduce( (total,item)=> {
    return total * item.length;
  },1);
  var res = [];
  for(let i=0;i<max;i++){
    res.push(getNum(arr,index));
    index = riseNum(index);
  }
  return res;
}

clever

function getPINs(observed) {
  var adjacent = [
    /* 0 */ [0, 8],
    /* 1 */ [1, 2, 4],
    /* 2 */ [1, 2, 3, 5],
    /* 3 */ [2, 3, 6],
    /* 4 */ [1, 4, 5, 7],
    /* 5 */ [2, 4, 5, 6, 8],
    /* 6 */ [3, 5, 6, 9],
    /* 7 */ [4, 7, 8],
    /* 8 */ [5, 7, 8, 9, 0],
    /* 9 */ [6, 8, 9]
  ];
  
  return observed
    .split('')
    .map(function(d) { return adjacent[d|0]; })
    .reduce(function(pa, da) {
      return da.reduce(function(pv, d) {
        return pv.concat(pa.map(function(p) {
          return '' + p + d;
        }));
      }, []);
    }, ['']);
}

Question from https://www.codewars.com/kata/the-observed-pin/solutions/javascript/me/best_practice

转载请注明出处: https://chrunlee.cn/article/js-code-war-pin.html


感谢支持!

赞赏支持
提交评论
评论信息 (请文明评论)
暂无评论,快来快来写想法...
推荐
今天小程序上传体验版本后莫名无法获取用户数据,但是本地开发环境是正常的,通过开发工具的真机进行测试也正常,但是通过开发工具的预览又不正常,初步来看代码是没有问题的,可能是哪里设置有问题。
在我们web开发过程中经常会碰到针对table的一些dom操作,这里整理一下关于这方面的知识点。当然我们可以通过jquery这样的插件来处理,或许会更简单一些,不过现在简单说下原生JS是如何操作的
this 是 JavaScript 的一大难点,多年经验的前端程序员都可能对这方面模糊。this 在大量的函数、类库中都有使用,理清显式绑定和隐式绑定有助于理解或书写这类函数。
之前一直没面试过前端,今天有一个,先整理下需要问的问题和答案。这里都是一些简单的问题,关于当下比较流行的框架并没有涉及到..
近期需求:将一棵树导出到excel中,树是ztree,通过插件Table2excel导出table到excel中。
在使用echarts 来做统计报表的时候,由于数量较多,准备将同类型的相同属性抽取出来,然后用来做默认属性的。结果发现一个问题
通过canvas可以进行画图实现一些动画效果等,今天练习下通过canvas来实现一个简易的电子画板,可以在白板上进行画画,然后指定不同的颜色、线条粗细,加载不同的背景以及擦除效果。
项目中需要使用treegrid,找了下easyui 和 ext都有,但是项目用的框架是 byyui,如果为了treegrid 就把这些都加载的话,感觉不太合算。找了大家常用的基于jquery的treegrid.