Codeforces--1051B--Relatively Prime Pairs

题目描述：
You are given a set of all integers from l to r inclusive, l

You want to split these numbers into exactly r−l+12 pairs in such a way that for each pair (i,j) the greatest common divisor of i and j is equal to 1. Each number should appear in exactly one of the pairs.

Print the resulting pairs or output that no solution exists. If there are multiple solutions, print any of them.
输入描述:
The only line contains two integers l and r (1≤l 输出描述:
If any solution exists, print “YES” in the first line. Each of the next r−l+12 lines should contain some pair of integers. GCD of numbers in each pair should be equal to 1. All (r−l+1) numbers should be pairwise distinct and should have values from l to r inclusive.

If there are multiple solutions, print any of them.

If there exists no solution, print “NO”.
输入：
4
8 5 2 3
6
1 1 1 2 2 2
输出：
164
27
题意：
问在区间内有多少对数互为质数。
题解：
一个数和他相邻的数一定是互为质数，枚举即可。
代码：

#include
#include
#include
#include
using namespace std;

typedef long long ll;

int main(){
    ll l,r;
    while(scanf("%lld%lld",&l,&r)!=EOF){
        printf("YES\n");
        for(ll i = l;i < r;i += 2){
            printf("%I64d %I64d\n",i,i + 1);
        }
    }
    return 0;
}