Left Rotate Array by K Positions

Code

#include <stdio.h>

void rotate_left(int arr[], int n, int k) {
    // handle case where rotations are useless
    if (n < 2)
        return;
        
    // make sure number of rotations not bigger than array
    k %= n;

    // perform k rotations
    while (k > 0) {
        // backup first element because about to be lost
        int backup = arr[0];
        for (int i = 1; i < n; i++) {
            // move each element to the previous position
            arr[i-1] = arr[i];
        }
        // put backup element at the end
        arr[n-1] = backup;
        // prepare next rotation
        k--;
    }
}

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

 

 

 

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Input

5 2 1 2 3 4 5

Expected Output

3 4 5 1 2