Rotate Array, rotatearray

Rotate Array, rotatearray

The questions are as follows:

Rotate an array of n elements to the right by k steps.

For example, with n = 7 and k = 3, the array[1,2,3,4,5,6,7]Is rotated[5,6,7,1,2,3,4].

Method 1:

var rotate = function(nums, k) {    var temp;    for (var i = 0; i < k ; i++) {        temp = nums.pop();        nums.unshift(temp);    }};

This method is simple, but the time complexity is a bit high.

Method 2:

var rotate = function(nums, k) {    var tNums = new Array();    var len = nums.length;    for (var i = 0; i < len; i++) {        tNums[i] = nums[i];    }    for (var j = 0; j < len; j++) {        nums[(j + k)%len] = tNums[j];     }};

In the second method, the time complexity is reduced, but the space complexity increases.

Method 3 (refer to self-clicking to open the link ):

Var rotate = function (nums, k) {<span style = "white-space: pre"> </span> var len = nums. length; var temp = nums [0]; // var startIndex = 0; var currentIndex = 0; for (var I = 0; I <len; I ++) {currentIndex = (currentIndex + k) % len; var swap = nums [currentIndex]; nums [currentIndex] = temp; temp = swap; // complete the switching of a ring if (currentIndex = startIndex) {currentIndex = ++ startIndex; temp = nums [currentIndex] ;}};

The time and space complexity of this method is very low.