Inverse Prime Depth analysis

Loaded from: http://blog.csdn.net/ACdreamers/article/details/25049767

Small Knowledge Points:

If you ask for the number of 756=2^2*3^3*7^1

(2+1) * (3+1) * (+) =24

Based on the above conclusions, the algorithm is given to search each quality factor in ascending order of factorization size, and enumerate each quality factor.

To prune:

Property One: The mass factor of an inverse prime is bound to be a continuous prime number starting from 2.

Because a maximum of 10 primes is required: 2,3,5,7,11,13,17,19,23,29

Nature two: P=2^t1*3^t2*5^t3*7^t4 ..... Inevitably t1>=t2>=t3>= ....

The problem encountered when learning the inverse prime.

Given a number, a minimum positive integer is obtained, making an approximate number of

Probably read. Build your search on every level. But I still don't understand.

1 #include <stdio.h>2 #include <String.h>3 #include <iostream>4UsingNamespaceStd56 typedef unsignedLongLongULL;7Const ULL INF = ~0ull;//Represents Infinity.89int p[16] = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53};//A number must be able to be split into prime numbers multiplied by the form,1011IntN12ULL ans;1314void Dfs (int dept, ULL TMP,int num) {//Dept indicates the depth of the search. Num is an approximate number of the current number. TMP indicates the number of current cable representations,15if (num > N)Return//If it's about a few numbers >n16if (num = = n && ans > tmp) ans = tmp;//If the approximate number is just n. And this number is smaller than the previous number, it is recorded,17for (int i=1; i<=63; ++i) {//In fact, I think it started from 0,???18if (Ans/p[dept] < TMP)Break//Don't know why this is the end of the loop condition. Or is this the end of the story???DFS (dept+1, tmp *= p[dept], num* (i+1));//I is the number of p[dept on behalf of this layer] this factor,20}21st}2223int Main () {( cin >> N) {. ans = INF;  DFS (0, 1, 1);  cout << ans << endl; // tried to output in C language. Did not try to come out, ...???    0;                     (+} 

Inverse Prime Depth analysis