Codeforces Round #362 (Div. 2) A. Pineapple Incident

A. Pineapple Incident
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Ted has a pineapple. This pineapple is able to bark like a bulldog! At time t (in seconds) it barks for the first time. Then every s seconds after it, it barks twice with 1 second interval. Thus it barks at times tt + st + s + 1t + 2st + 2s + 1, etc.

Barney woke up in the morning and wants to eat the pineapple, but he can't eat it when it's barking. Barney plans to eat it at time x (in seconds), so he asked you to tell him if it's gonna bark at that time.

Input

The first and only line of input contains three integers ts and x (0 ≤ t, x ≤ 1092 ≤ s ≤ 109) — the time the pineapple barks for the first time, the pineapple barking interval, and the time Barney wants to eat the pineapple respectively.

Output

Print a single "YES" (without quotes) if the pineapple will bark at time x or a single "NO" (without quotes) otherwise in the only line of output.

Examples
input
3 10 4
output
NO
input
3 10 3
output
YES
input
3 8 51
output
YES
input
3 8 52
output
YES
Note

In the first and the second sample cases pineapple will bark at moments 31314, ..., so it won't bark at the moment 4 and will bark at the moment 3.

In the third and fourth sample cases pineapple will bark at moments 311121920272835364344515259, ..., so it will bark at both moments 51 and 52.

题意

接收t,s,x,从t秒开始,每间隔s秒,s+1秒,2s秒,2s+1秒pineapple就会叫一声,如果x秒的时候pineapple叫了那么我们输出NO,反之YES。

代码

#include <bits/stdc++.h>
using namespace std;
int main()
{
	//freopen("cin.txt","r",stdin);
    int i,j,n,a;
    cin>>i>>j>>n;
    if(n==i){
        cout<<"YES"<<endl;
        return 0;
    }
    n-=i;
    if((n%j==0||n%j==1)&&n>=j){
        cout<<"YES"<<endl;
        return 0;
    }
    cout<<"NO"<<endl;
	return 0;
}



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转载自blog.csdn.net/ontheway0101/article/details/52891976