JavaScript fun: Arrangement and combination practice

First, let's look at this figure, which is similar to the buttons on the desktop of an old-fashioned tablet phone. First, let's look at this figure, which is similar to the buttons on the desktop of an old-fashioned tablet phone.

Step 1: Create a ing based on the relationship between the number key and the corresponding letter.

var map = {      1 : [ 1 ],      2 : [ "A", "B", "C" ],      3 : [ "D", "E", "F" ],      4 : [ "G", "H", "I" ],      5 : [ "J", "K", "L" ],      6 : [ "M", "N", "O" ],      7 : [ "P", "Q", "R", "S" ],      8 : [ "T", "U", "V" ],      9 : [ "W", "X", "Y", "Z" ],      0 : [ 0 ]  };

Step 2: use recursion to solve the permutation and combination

function telephoneWords(digitString) {      var array = [];      var result = [];      digitString.split("").forEach(function(e) {          array.push(map[e]);      })      var traverse = function foo(from, to) {          if (to.length < 4) {              var cur = from.shift();              for (var i = 0; i < cur.length; i++) {                  var newTo = to.slice(0);                  newTo.push(cur[i]);                  var newFrom = from.slice(0);                  foo(newFrom, newTo);              }          } else {              result.push(to.join(""));          }      };      traverse(array, []);      return result;  }

The above are JavaScript interesting questions: arrange and combine the actual content. For more information, see the PHP Chinese website (www.php1.cn )!