按照紫书的思路,先求出所有的素数因子,然后递推求解并且记录,最后判断打印最终的结果即可,具体实现见如下代码:
#include<iostream>
#include<vector>
#include<string>
#include<set>
#include<stack>
#include<queue>
#include<map>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<sstream>
#include<cstdio>
#include<deque>
#include<functional>
using namespace std;
int n, m;
vector<int> prime;
void getPrime(){
int t = floor(sqrt(m)+0.5);
int m2 = m;
for (int i = 2; i <= t; i++){
if (m2%i == 0){
prime.push_back(i);
while (m2%i == 0) m2 = m2 / i;
}
}
if (m2 > 1) prime.push_back(m2);
}
int main(){
while (cin >> n >> m){
prime.clear();
n--;
getPrime();
//C(n,k)=C(n,k-1)*(n-k+1)/k
int flag[100010];
memset(flag, 0, sizeof(flag));
for (int i = 0; i < prime.size(); i++){
int fac = prime[i];
int count_e = 0;
int min_e = 0;
int m1 = m;
while (m1%fac == 0){
m1 = m1 / fac;
min_e++;
}
for (int k = 1; k < n; k++){
int up = n - k + 1;
int down = k;
while (up%fac == 0){
up = up / fac;
count_e++;
}
while (down%fac == 0){
down = down / fac;
count_e--;
}
if (count_e < min_e){
flag[k] = 1;
}
}
}
vector<int> res;
for (int i = 1; i < n; i++){
if (!flag[i]) res.push_back(i+1);
}
cout << res.size() << endl;
if (!res.empty()){
cout << res[0];
for (int i = 1; i < res.size(); i++){
cout << " " << res[i];
}
}
cout << endl;
}
return 0;
}