全排列算法 - JavaScript 实现

permgen.js

var a = [ 1, 2, 3 ];

function change( a, i, j) {
   var t = a[i];
   a[i] = a[j];
   a[j] = t;
}

function permgen( a, n ) {
   n = n == null ? a.length : n;
   if ( n <= 0 ) {
       return console.log( a );
   }
   for ( var i = 0; i < n; i++ ) {
    change( a, i, n - 1);
    permgen( a, n-1 );
    change( a, i, n - 1);
   }
}

permgen( a );