The observed PIN - my solution

The observed PIN - my solution

月光魔力鸭

2018-10-25 08:37 阅读 2483 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
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
jsQR 是一款纯粹的由javascript实现的二维码识别库,可以在浏览器端使用,也可以在后端node.js环境使用。我之前使用过其他的识别库,例如:qrcode-reader 或其他,在使用上都比较麻烦,而且识别率并不高。jsQR是后来发现的,感觉(没有实际对比验证)jsQR识别率要更高些,使用起来也更简单,不需要安装其他依赖软件。
最近一直在想着抓一些网盘数据,进行资料归拢,可是当我真正开始的时候.. 还是遇到了反爬,当然我本身就有心理预期,这是肯定会碰到的,只是没想到会在代理IP上耗费这么久,之前的时候也处理过代理IP ,可是由于一知半解,导致很多配置都不理解,debug全靠猜...
今天刷codewars的题目的时候碰到一个通过js来实现字符串转base64的题目,base64虽然在js或nodejs中经常用,但是我还真没有仔细去看过原理以及如何实现,这回绕不过去了,赶紧找了找资料看了下。
codewars上的一个题目,这里记录下解决方法。
在项目开发过程中,分页是少不了的,之前封装了一个分页组件,样式是基于bootstrap的样式,当然也可以自己来修改
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。
在开发过程中经常会碰到跨frame 去操作的需求,那么如何获得这个frame呢,这里写了一个工具类,用来通过name获得frame的jq对象