Left Rotate Array by K Positions

Code

#include <stdio.h>

void reverse(int arr[], int left, int right){
    while(left < right){
        int temp = arr[left];
        arr[left] = arr[right];
        arr[right] = temp;
        left++;
        right--;
    }
}

void rotate_left(int arr[], int n, int k) {
    // Your logic here
    k = k % n;
    reverse(arr, 0, k - 1);
    reverse(arr, k, n - 1);
    reverse(arr, 0, n - 1);
}

int main() {
    int n, k;
    scanf("%d %d", &n, &k);

    int arr[100];

    // Read array elements
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    // Rotate the array
    rotate_left(arr, n, k);

    // Print the rotated array
    for (int i = 0; i < n; i++) {
        printf("%d", arr[i]);
        if(i < n-1){
        	printf(" ");
        }
    }

    return 0;
}

Solving Approach

Reverse 0 - K elements first, then K - n, and then reverse the whole array.

 

 

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Input

5 2 1 2 3 4 5

Expected Output

3 4 5 1 2