189. Rotate Array

Given an array, rotate the array to the right by k steps, where k is non-negative.

Example 1:

Input:

[1,2,3,4,5,6,7] and

k

= 3

Output:

[5,6,7,1,2,3,4]

Explanation:

rotate 1 steps to the right: [7,1,2,3,4,5,6] rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]

Example 2:

Input:

[-1,-100,3,99] and

k

= 2

Output:

[3,99,-1,-100]

Explanation:

rotate 1 steps to the right: [99,-1,-100,3] rotate 2 steps to the right: [3,99,-1,-100]

Note:

• Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
• Could you do it in-place with O(1) extra space?

In place rotate

class Solution {

/**
* @param Integer[] \$nums
* @param Integer \$k
* @return NULL
*/
function rotate(&\$nums, \$k) {
\$c = count(\$nums);
\$steps = 0;
\$start = 0;

while(\$steps < \$c){
\$i = \$start;
\$prev = \$nums[\$i];
do{
\$next = (\$i+\$k)%\$c;
\$temp = \$nums[\$next];
\$nums[\$next] = \$prev;
\$prev = \$temp;
\$i += \$k;
\$i = \$i % \$c;
\$steps++;
}while(\$start != \$i);
\$start ++;

}

}
}

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