HDU 2136 (Prime number filter + integer decomposition)

Largest prime factor

Time limit:5000/1000 MS (java/others) Memory limit:32768/32768 K (java/others)
Total submission (s): 9993 Accepted Submission (s): 3528

Problem Descriptioneverybody knows any number can is combined by the prime number.
Now, your task was telling me what position of the largest prime factor.
The position of Prime 2 is 1, Prime 3 are 2, and Prime 5 is 3, etc.
Specially, LPF (1) = 0.

Inputeach line would contain one integer n (0 < n < 1000000).

Outputoutput the LPF (n).

Sample Input12345

Sample Output01213

#include <stdio.h>#include<math.h>#include<iostream>#include<algorithm>#include<string.h>#include<stdlib.h>using namespaceStd;typedefLong LongLL;Const intN =1000000;BOOLP[n];///to False represents a prime numberintIdx[n];voidinit () {memset (P,false,sizeof(p)); intID =1;  for(intI=2; i<n;i++){        if(!P[i]) {Idx[i]= id++;  for(ll j= (LL) i*i;j<n;j+=i) {P[j]=true; }        }    }}intGetmax (intN) {    intMax =-1;  for(intI=2; i*i<=n;i++){        if(n%i==0){             while(n%i==0) {n/=i; } Max=Max (I,max); }    }    if(n>1) Max =Max (max,n); returnMax;}intMain () {init (); intN;  while(SCANF ("%d", &n)! =EOF) {        if(n==1) printf ("0\n"); Else{            intMax =Getmax (n); printf ("%d\n", Idx[max]); }    }}

HDU 2136 (Prime number filter + integer decomposition)