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 C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;

namespace easy_Atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            double[] AV = Array.ConvertAll(Console.ReadLine().Split(),double.Parse);
            double A = AV[0];
            double V = AV[1];
            double[] BW = Array.ConvertAll(Console.ReadLine().Split(),double.Parse);
            double B = BW[0];
            double W = BW[1];
            ulong T = ulong.Parse(Console.ReadLine());
            bool flag = false;
            if(V-W>0){
                ulong test =(ulong)((B-A)/(V-W)); 
                if(test<=T){
                    flag=true;
                }
            }
            Console.WriteLine(flag?"YES":"NO");
        }   
            // float[] ABN = Array.ConvertAll(Console.ReadLine().Split(),float.Parse);
            // long[] NK = Array.ConvertAll(Console.ReadLine().Split(),long.Parse);
            // long N = NK[0];
            // long K = NK[1];
            // long K = long.Parse(Console.ReadLine());
            // int[] abc = Array.ConvertAll(Console.ReadLine().Split(),int.Parse);
            // string S = Console.ReadLine();
            // int x = int.Parse(Console.ReadLine());
            // int b = int.Parse(Console.ReadLine());
            // int N = int.Parse(Console.ReadLine());
            // float N = float.Parse(Console.ReadLine());
            // string c = Console.ReadLine();
            // string B = Console.ReadLine();
            // string[] s = Console.ReadLine().Split();
            // var s = (new string[] { Console.ReadLine(), Console.ReadLine(), Console.ReadLine() }).Select(float.Parse);
            // float[] a = Array.ConvertAll(Console.ReadLine().Split(),float.Parse);
            // var X = Console.ReadLine();
            // int[,] abcd = new int[NMQ[2],4];
            // int[] A = new int[NMQ[0]];
            // int[] A_num = new int[NMQ[0]];
            // long[] s=Array.ConvertAll(Console.ReadLine().Split(),long.Parse);
            // var hs=new Dictionary<long,long>();
            // for(int i=0;i<s[0];i++){
            //     long[] q=Array.ConvertAll(Console.ReadLine().Split(),long.Parse);
            //     if(hs.ContainsKey(q[0])){hs[q[0]]+=q[1];}
            //     else{hs.Add(q[0],q[1]);}
            // }
        
        // //最小公倍数
        // static long Lcm(long a, long b)
        // {
        //     return a/Gcd(a,b)*b;
        // }

        // //最大公約数
        // static long Gcd(long m, long n)
        // {
        //     if(n==0)return m;
        //     return Gcd(n,m%n);
        // }
    }
}