标签:blog io os for sp div c log amp
求不比M大的可以被集合任一个数整除的数的个数。(容斥原理)
#include <iostream> #include <cstdio> #include <algorithm> #include <cstring> using namespace std; int set[15]; int ans; int gcd(int a,int b){ if(b==0) return a; return gcd(b,a%b); } void dfs(int i,int num,int p,int m,int n){ if(i>=n){ if(num==0) ans=0; else if(num&1) ans+=(m/p); else ans-=(m/p); return; } dfs(i+1,num,p,m,n); dfs(i+1,num+1,p/gcd(p,set[i])*set[i],m,n); } int main(){ int n,m; while(scanf("%d%d",&n,&m)!=EOF){ for(int i=0;i<n;i++) scanf("%d",&set[i]); dfs(0,0,1,m,n); printf("%d\n",ans); } return 0; }
标签:blog io os for sp div c log amp
原文地址:http://www.cnblogs.com/jie-dcai/p/4004145.html