求区间[L,R]的整数中哪一个的正约数最多。
一个数因数分解后, 它的约数Cnt = (a[j]+1) 的乘积 ,j是每个因数的个数
#include <iostream> #include <cstring> #include <cmath> #include <algorithm> using namespace std ; const int M=1e5+30; #define int long long int b[M],prime[M],tot,n; void init(int top){ memset(b,1,sizeof b); b[1]=0; int i,j; for(i=2;i<=top;i++){ if(b[i]) prime[++tot]=i; for(j=1;j<=tot&&i*prime[j]<=top;j++){ b[i*prime[j]]=0; if(i%prime[j]==0) break; } } } int Count(int x){ int i,s=1,cnt; for(i=1;prime[i]*prime[i]<=x;i++){ cnt=1; if(x%prime[i]==0){ while(x%prime[i]==0) x/=prime[i],cnt++; s*=cnt; } } if(x>1) s*=2; return s; } signed main(){ int tes,L,R; init(1e5); cin>>tes; while(tes--){ cin>>L>>R; int ans=0,id=0; for(int i=L;i<=R;i++){ int x =Count(i); if(x>ans) ans=x,id=i; } printf("Between %d and %d, %d has a maximum of %d divisors." ,L,R,id,ans); puts(""); } }
标签:tes,int,id,1e5,ans,UVA,294,include,Divisors From: https://www.cnblogs.com/towboa/p/17305884.html