Left Rotate Array by K Positions

Code

#include <stdio.h>

void reversed_arr(int arr[], int *left, int *right) {
    while (left < right) {
        int temp = *left;
        *left = *right;
        *right = temp;

        left++;
        right--;
    }
}

void rotate_left(int arr[], int n, int k) {
    // Your logic here
    k %= n; //vi k = n thi arr quay lai nhu cu ==> chi lay phan dư là đủ
    //VD arr [1 2 3 4 5], n = 5, k = 2
    reversed_arr(arr, &arr[0], &arr[k - 1]);    //rev đoạn đầu -> k: [2 1 3 4 5]
    reversed_arr(arr, &arr[k], &arr[n - 1]);    //rev đoạn k -> cuối arr: [2 1 5 4 3]
    reversed_arr(arr, &arr[0], &arr[n - 1]);    //rev toàn bộ arr: [3 4 5 1 2]
}

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