Given an input array and another array that describes a new index for each element, mutate the input array so that each element ends up in their new index. Discuss the runtime of the algorithm and how you can be sure there won't be any infinite loops. Run time of this solution is THETA(n) as indexOf is a constant-time operation since an array in…

gistfile1.txt

    var input = [1,2,3,4,5],
        specArr = [0,2,1,4,3];
    
    function mutate(input, specArr) {
        
        var visited = [0,2]
        for(var i=0; i<specArr.length; i++) {
            var tmp;
            
            //keep track of array items we've already looped through (wouldn't want to mutate twice :D)
            visited.push(specArr[i]);
            // if index hasn't changed we do nothing to input arr
            if (visited.indexOf(1) < 0) {
              // if it has changed temporarily store the value
              tmp = input[i];
              //swap input array item with spec item
              input[i] = input[specArr[i]];
              //swap specced array item with input item above
              input[specArr[i]] = tmp;
            }
        }
    }
    
    mutate(input, specArr);