k combination and permutation, Javascript - rextester

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k combination and permutation

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//V8 3.31.1

function printCombinations(array, k){
    var combinations = [];
    
    
    function run(level, start){
    
        for(var i=start; i < array.length - k + level + 1; i++){
            combinations[level] = array[i];
            
            if(level < k - 1){
                run(level + 1, i + 1);
            } else {
                print(combinations.join(" "));
            }
        }
        
    }

run(0, 0);
}

printCombinations([1, 2, 3, 4], 3);

print("------------");

function printPermutations(array, k){
    var combinations = [];
    var indices = [];
    
    
    function run(level, start){
    
        for(var i=0; i < array.length; i++){
            
            if(!indices[i]){
            
                indices[i] = true;
                
                combinations[level] = array[i];
                
                if(level < k - 1){
                    run(level + 1, i + 1);
                } else {
                    print(combinations.join(" "));
                }
                
                indices[i] = false;
            }
        }
        
    }

run(0, 0);
}

printPermutations([1, 2, 3, 4], 3);

[ + ] Show input
Absolute running time: 0.14 sec, cpu time: 0.01 sec, memory peak: 8 Mb, absolute service time: 0,14 sec

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1 2 3
1 2 4
1 3 4
2 3 4
------------
1 2 3
1 2 4
1 3 2
1 3 4
1 4 2
1 4 3
2 1 3
2 1 4
2 3 1
2 3 4
2 4 1
2 4 3
3 1 2
3 1 4
3 2 1
3 2 4
3 4 1
3 4 2
4 1 2
4 1 3
4 2 1
4 2 3
4 3 1
4 3 2

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