703085. Swap kth elements
Swap kth elements5500
Summary
The problem is to swap the kth element in a given array with another element. The key concepts involved are arrays and data structures, indicating that this is a basic algorithmic problem.
Detailed Explanation
The approach for solving this problem involves using two pointers: one at the beginning of the array and another at the kth position from the start. We then swap the elements at these positions and move the first pointer forward by k steps. This process continues until we have processed all elements in the array.
Here is a step-by-step breakdown of the solution:
- Initialize two pointers,
iandj, to 0. - Move the second pointer
jto the kth position from the start (i.e.,j = k - 1). - Swap the elements at positions
iandj. - Increment
ibyksteps. - Repeat steps 2-4 until we have processed all elements in the array.
The time complexity of this algorithm is O(n), where n is the size of the input array, since we process each element once. The space complexity is O(1), as we only use a constant amount of space to store the pointers and temporary variables.
Optimized Solutions
Java
public static void swapKthElements(int[] arr, int k) {
for (int i = 0; i < arr.length; i += k) {
int temp = arr[i];
arr[i] = arr[k - 1];
arr[k - 1] = temp;
}
}