50pts求救

#include<bits/stdc++.h>

using namespace std;


int n,y,s,t;

int look[35];

int inter[35];
 
int main() {
	
	cin >> n >> y >> s >> t;
	
	if (s>t){
		cout << "No";
		return 0;
	}
	look[1] = y;
	inter[1] = 0;
	for (int i = 2 ; i <= n+1 ; i ++) {
		look[i] = (i-1) * t + y;
		inter[i] = (i-1)*s;
//		cout << look[i] << '\n' << i;
	}
	
	
	for (int i = 1 ; i <= n+1 ; i ++) {
		for (int j = 1 ; j <= n ; j ++) {
			if (inter[i]>look[j] && inter[i+1] < look[j+1] && i <= n) {
				cout << "Yes";
//				cout << i << " " << j ;
				
				return 0;
			}	
		}
	}
	
	cout << "No";
	
	
	return 0;
}
//10 30 15 30