The correct, optimal and working solution for programming question array-left-rotation on hackerrank

/* * Author: Arpit Bhayani * https://arpitbhayani.me */ #include <cmath> #include <cstdio> #include <cstdlib> #include <climits> #include <deque> #include <iostream> #include <list> #include <limits> #include <map> #include <queue> #include <set> #include <stack> #include <vector> #define ll long long #define MIN(a, b) a < b ? a : b #define MAX(a, b) a > b ? a : b using namespace std; int readline(char *str) { int i = 0; char ch; while((ch = getchar()) != '\n') { str[i++] = ch; } str[i] = '\0'; return i; } int arr[100010]; void reverse(int start, int end) { while(start < end) { int t = arr[start]; arr[start] = arr[end]; arr[end] = t; start++; end--; } } int main(int argc, char *argv[]) { int n, k; scanf("%d%d", &n, &k); for(int i = 0 ; i < n ; i ++) { scanf("%d", &arr[i]); } reverse(0, n-1); reverse(0, n-k-1); reverse(n-k, n-1); for(int i = 0 ; i < n ; i ++) { printf("%d ", arr[i]); } printf("\n"); return 0; }