There are two kangaroos on an x-axis ready to jump in the positive direction (i.e, toward positive infinity). The first kangaroo starts at location x1 and moves at a rate of v1 meters per jump. The second kangaroo starts at location x2 and moves at a rate of v2 meters per jump. Given the starting locations and movement rates for each kangaroo, can you determine if they'll ever land at the same location at the same time?

#include <iostream>
using namespace std;

int main(){
    int x1, v1, x2, v2;
    cin >> x1 >> v1 >> x2 >> v2;

    // If one kangaroo is behind the other AND moving slower,
    //    he/she will never catch up to the other one
    if ((x1 < x2) && (v1 < v2)) cout << "NO";
    else if ((x2 < x1) && (v2 < v1)) cout << "NO";

    // Otherwise, move each kangaroo one jump at a time until
    //     the one behind is no longer behind.
    else {
        if (x1 < x2) {
            while (x1 < x2) {
                x1 += v1;
                x2 += v2;
            }
        } else {
            while (x2 < x1) {
                x1 += v1;
                x2 += v2;
            }
        }

        // Once he/she is no longer behind the other, check to see
        //    if he/she is in the same position, or if he/she has passed
        if (x1 == x2) cout << "YES";
        else cout << "NO";
    }
    return 0;
}