"Bzoj" "1053" "HAOI2007" anti-prime ant

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Classic Search topic (in fact, Konjac Konjac will only search ... vfleaking seems to have better practices? ）

Enumerate the powers of prime numbers, in fact not much depth ... Because the $2^32$ is more than n ... And the prime number can not be taken too big, so will not explode ...

1 /**************************************************************2 problem:10533 User:tunix4 language:c++5 result:accepted6 time:40 Ms7 memory:1760 KB8 ****************************************************************/9  Ten //Bzoj 1053 One#include <cmath> A#include <vector> -#include <cstdio> -#include <cstring> the#include <cstdlib> -#include <iostream> -#include <algorithm> - #defineRep (i,n) for (int i=0;i<n;++i) + #defineF (i,j,n) for (int i=j;i<=n;++i) - #defineD (i,j,n) for (int i=j;i>=n;--i) + #definePB Push_back A using namespacestd; atInlineintGetint () { -     intv=0, sign=1;CharCh=GetChar (); -      while(ch<'0'|| Ch>'9'){if(ch=='-') sign=-1; Ch=GetChar ();} -      while(ch>='0'&&ch<='9') {v=v*Ten+ch-'0'; Ch=GetChar ();} -     returnv*Sign ; - } in Const intn=2e9,inf=~0u>>2; -typedefLong LongLL; to /******************tamplate*********************/ + intn,prime[100010],tot; -LL mx=0, ans=0; the BOOLvis[100010]; * //First x prime number, the total product is now, because several numbers are M $ voidDfsintX,ll Now,ll m,intLim) {Panax Notoginseng     if(M>mx && now<=N) { -Mx=m; cn1=Now ; the     } +     if(m==mx && Now<ans && now<=n) ans=Now ; A     if(x> -)return; theLL p=Now ; +F (I,1, Lim) { -         if(p*prime[x]>n) Break; $p*=Prime[x]; $DFS (x+1, p,m* (i+1), lim-i); -     } - } the intMain () { - #ifndef Online_judgeWuyiFreopen ("1053.in","R", stdin); theFreopen ("1053.out","W", stdout); - #endif Wuscanf"%d",&n); -F (I,2, sqrt (N)) { About         if(!Vis[i]) { $prime[++tot]=i; -              for(intJ=I*I;J&LT;=SQRT (N); j+=i) vis[j]=1; -         } -     } ADfs1,1,1, -); +printf"%lld\n", ans); the     return 0; -}

View Code 1053: [HAOI2007] anti-prime ant time limit:10 Sec Memory limit:162 MB
submit:1821 solved:1014
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For any positive integer x, the number of its approximate numbers is recorded as g (x). For example G (1) =1, g (6) = 4.
If a positive integer x satisfies: g (x) >g (i) 0<i<x, it is said that X is an inverse prime number. For example, integer 1,2,4,6, etc. are all anti-prime.
Now given a number n, can you find the largest anti-prime that does not exceed n?

Input

A number N (1<=n<=2,000,000,000).

Output

The maximum number of anti-prime numbers not exceeding N.

Sample Input +Sample Output840Hintsource [Submit] [Status] [Discuss]

"Bzoj" "1053" "HAOI2007" anti-prime ant