kangaroo.cpp

// https://www.hackerrank.com/challenges/kangaroo/

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

/*
 * Complete the 'kangaroo' function below.
 *
 * The function is expected to return a STRING.
 * The function accepts following parameters:
 *  1. INTEGER x1
 *  2. INTEGER v1
 *  3. INTEGER x2
 *  4. INTEGER v2
 */

string kangaroo(int x1, int v1, int x2, int v2)
{
	int distance1 = x1 + v1;
	int distance2 = x2 + v2;
	int maxLimit = 10000;
	bool found = false;

	while (maxLimit > 0)
	{
		// Check if both starting position and velocity of one kagaroo is greater than the other
		// Check if their relative time is same i.e no remainder (time = distance / velocity)
		if (((x2 - x1) * (v2 - v1) < 0) && ((x2 - x1) % (v2 - v1) == 0))
		{
			found = true;
			break;
		}
		else
		{
			distance1 += v1;
			distance2 += v2;
		}
		maxLimit--;
	}

	if (found)
	{
		return "YES";
	}
	else
	{
		return "NO";
	}
}

int main()
{
	ofstream fout(getenv("OUTPUT_PATH"));

	string first_multiple_input_temp;
	getline(cin, first_multiple_input_temp);

	vector<string> first_multiple_input = split(rtrim(first_multiple_input_temp));

	int x1 = stoi(first_multiple_input[0]);

	int v1 = stoi(first_multiple_input[1]);

	int x2 = stoi(first_multiple_input[2]);

	int v2 = stoi(first_multiple_input[3]);

	string result = kangaroo(x1, v1, x2, v2);

	fout << result << "\n";

	fout.close();

	return 0;
}

string ltrim(const string &str)
{
	string s(str);

	s.erase(
		s.begin(),
		find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace))));

	return s;
}

string rtrim(const string &str)
{
	string s(str);

	s.erase(
		find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
		s.end());

	return s;
}

vector<string> split(const string &str)
{
	vector<string> tokens;

	string::size_type start = 0;
	string::size_type end = 0;

	while ((end = str.find(" ", start)) != string::npos)
	{
		tokens.push_back(str.substr(start, end - start));

		start = end + 1;
	}

	tokens.push_back(str.substr(start));

	return tokens;
}