SEPA : Simple Efficient Permutation Algorithm
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/**
* A Javascript implmentation of the Simple Efficient Permutation Algorithm (SEPA)
* Source : [http://www.quickperm.org/soda_submit.php]
**/
function swap( target, i, j ){
if( target ){
let temp = target[i];
target[i] = target[j];
target[j] = temp;
return target;
}
return target;
}
function permute( target ){
let length = target.length;
let key = length-1;
let newKey = length-1;
while( key > 0 && target[key] <= target[key-1] ){
key--;
}
key--;
if( key < 0 ){
return 0;
}
newKey = length-1;
while( newKey > key && target[newKey] <= target[key] ){
newKey--;
}
swap( target, key, newKey );
length--;
key++;
while( length > key ){
swap( target, length, key );
key++;
length--;
}
return 1;
}
let test = 'cac';
let target = test.split('');
let permutations = [];
do{
permutations.push( target.join('') );
} while( permute(target) );
console.log( `Permuations : ${permutations.length}\n${permutations.join("\n")}` );
JavaScript
INFO