The observed PIN - my solution

The observed PIN - my solution

月光魔力鸭

2018-10-25 08:37 阅读 257 喜欢 0 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


如果对你有用的话,请赏给作者一个馒头吧 ...或帮点下页面底部的广告,感谢!!

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
web开发中,前台有时候会需要一个随机数或序列,通常来说,这个随机数可能只在当前页面中使用,并不需要太过严格,大体上重复率低即可。
我们经常会有判断一个数值是素数的需求,那么我们如何来实现呢?
在开发过程中多个页面使用的一个小工具类,简单完善了下,还算不错,给各位提供下小思路。
关于jquery,他的核心特点就是无new构造和链式调用,这里根据网上的资料,自己简单理解下,有助于消化核心代码。
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。
java 对象中有很多引用,甚至会出现循环引用,比如 user 对象中有 school 对象,school 对象中又有 user 对象,这样在对 user 对象序列化的时候,就会出现死循环,导致内存溢出。通过一定的方式,将每个对象增加ID 和 REF 引用标识最终可以解决这个问题
web网站上总会有在文本域中提交代码的操作,那么如何处理呢?