Problem:
Score : 200 points

Problem Statement

Two children are playing tag on a number line. (In the game of tag, the child called "it" tries to catch the other child.) The child who is "it" is now at coordinate A, and he can travel the distance of V per second.
The other child is now at coordinate B, and she can travel the distance of W per second.

He can catch her when his coordinate is the same as hers.
Determine whether he can catch her within T seconds (including exactly T seconds later).
We assume that both children move optimally.

Constraints

-10^9 \leq A,B \leq 10^9

1 \leq V,W \leq 10^9

1 \leq T \leq 10^9

A \neq B

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A V
B W
T

Output

If "it" can catch the other child, print YES; otherwise, print NO.

Sample Input 1

1 2
3 1
3

Sample Output 1

YES

Sample Input 2

1 2
3 2
3

Sample Output 2

NO

Sample Input 3

1 2
3 3
3

Sample Output 3

NO

Solution in Java (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long a = sc.nextLong();
		long v = sc.nextLong();
		long b = sc.nextLong();
		long w = sc.nextLong();
		long t = sc.nextLong();
		sc.close();

		if (a < b) {// 鬼が後ろにいる
			BigInteger bigT = BigInteger.valueOf(t);
			BigInteger avt = BigInteger.valueOf(a).add(BigInteger.valueOf(v).multiply(bigT));
			BigInteger bwt = BigInteger.valueOf(b).add(BigInteger.valueOf(w).multiply(bigT));

			if (avt.compareTo(bwt) != -1) {
				System.out.println("YES");
			} else {
				System.out.println("NO");
			}
			return;
		} else { // 鬼が前にいる
			do {
				b += w;
				if (a <= b) {
					System.out.println("YES");
					return;
				}
				a += v;
			} while (--t != 0);
			System.out.println("NO");
		}
	}
}