Arrays Left Rotation

Arrays: Left Rotation – (Easy)

Description:

A left rotation operation on an array of size shifts each of the array’s elements unit to the left. For example, if left rotations are performed on array , then the array would become .

Given an array of integers and a number, , perform left rotations on the array. Then print the updated array as a single line of space-separated integers.

Input Format

The first line contains two space-separated integers denoting the respective values of (the number of integers) and (the number of left rotations you must perform).
The second line contains space-separated integers describing the respective elements of the array’s initial state.

Constraints

Output Format

Print a single line of space-separated integers denoting the final state of the array after performing left rotations.

Sample Input

5 4
1 2 3 4 5

Sample Output

5 1 2 3 4

Explanation

When we perform left rotations, the array undergoes the following sequence of changes:

Thus, we print the array’s final state as a single line of space-separated values, which is 5 1 2 3 4.

Solution:

My Code:

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>

#include <string>
#include <sstream>
#include <iterator>

using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    string line;
    int problems;
    getline(cin, line);
    if (line == "") { return -1; } // No STDIN
    stringstream(line) >> problems;
    if (!problems) { return 0; } // No points
    for (int i = 0; i < problems; i++) {
        int px, py, qx, qy;
        getline(cin, line); // Get a line and store entirity in a string
        istringstream iss(line); // Create an istringstream object which is parsed by space (" ") from input string.
        
        /*
        vector<string> points((istream_iterator<string>(iss)),
                              istream_iterator<string>());
        stringstream(points[0]) >> px;
        stringstream(points[1]) >> py;
        stringstream(points[2]) >> qx;
        stringstream(points[3]) >> qy;
        */
        
        iss >> px;
        iss >> py;
        iss >> qx;
        iss >> qy;
        int rx = 2 * qx - px; // qx - (px - qx)
        int ry = 2 * qy - py; // qy - (py - qy)
        cout << rx << " " << ry << endl;
    }
    return 0;
}

Code Blog Wasif Islam

Arrays Left Rotation