题面
Given (l) and (k), Cuber QQ wants you to answer if there are more than (k) primes (i.e., at least (k+1) primes) in ([l,l+2k)).
Input
One line with two space-separated integers (l,k(1≤l,k≤10^8)).
Output
One line with "Yes" or "No".
Examples
Input
3 3
Output
No
Input
2 1
Output
Yes
题目分析
任选一个([l,l+2k))的区间,会发现,对于大部分长度为(2k-1)的区间,奇数数量满足(num_{Odd}le k)的关系,但是有一组特殊的范围:([2,3],[2,3,4,5],[2,3,4,5,6,7])满足(num_{Odd}>k),所以得到答案:只有(l=2,1le kle 3)时输出Yes
,其余情况输出No
AC 代码足
AC 代码
#include <bits/stdc++.h>
#define io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;
long long l, k;
int main() {
io;
cin >> l >> k;
if(l == 2) {
if(k >= 1 && k <= 3) puts("Yes");
else puts("No");
} else puts("No");
return 0;
}