The observed PIN - my solution

The observed PIN - my solution

月光魔力鸭

2018-10-25 08:37 阅读 2654 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
如何通过js调用本地摄像头呢?获取后如何对视频进行截图呢?在这里跟大家做一个简易的Demo来实现以上几个功能。
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。
之前的时候都是在各大主机厂商手动进行申请免费的,直到阿里的免费期限变更为3个月.. 我就开始觉的有些麻烦了,还不如使用这个let's encrypt进行部署呢。
需求如下:有一张大图,需要显示大图中的一小部分,目前能知道的时候小图的宽高和坐标,同时大图有一个旋转角度可以知道,目标就是把小图正确的显示出来。
通过jspdf ,我们可以将页面或图片生成pdf下载下来,如果是一些复杂的页面,我们可以将页面转成图片,然后把图片加入到pdf中,生成并下载。
对于web开发过程中的JS对象 Array ,我们真的充分使用了么?是不是理解了Array的全部?能够在合适的地点调用合适的函数,使用合适的属性?
错误:The operation is insecure . 在使用canvas的 toDataUrl的时候报错,看了很多资料,基本上都说是设置跨域,但是我一直都有的啊。其实,只是顺序错了,setAttribute('crossOrigin','Anonymous') 要在设置 src之前设置。
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。