POJ 3421 X-factor Chains

Linear prime sieve + mass factor decomposition + combination number.

AC found this to be a little less efficient. 766ms.

#include <stdio.h>#include<string.h>#include<stdlib.h>#include<time.h>#include<iostream>#include<algorithm>#include<cmath>using namespaceStd;typedefLong LongLL;intTol; LL factor[ -];Const intN =2000001; LL Prime[n]= {0},num_prime =0;intIsnotprime[n] = {1,1};voidFINDFAC (Long LongN) {     for(intI=0; i<num_prime; i++)    {        if(n%prime[i]!=0)Continue;  while(1)        {            if(n==1|| n%prime[i]!=0) Break; Factor[tol++]=Prime[i]; N=n/Prime[i]; }        if(n==1) Break; }}intnum[ -],tot;Long Longc[ -][ -];voidinit () {c[1][1]=1;  for(intI=1; i<= -; i++) c[i][0]=1;  for(intI=2; i<= -; i++)    {         for(intj=1; j<= -; J + +) {C[i][j]=c[i-1][j-1]+c[i-1][j]; }    }     for(Longi =2; i < N; i + +)    {        if(!Isnotprime[i]) prime[num_prime++]=i;  for(Longj =0; J < num_prime && I * prime[j] < N; J + +) {Isnotprime[i* Prime[j]] =1; if( ! IPrime[j]))  Break; }    }}intMain () {init (); Long LongN;  while(~SCANF ("%lld",&N)) {if(n==1) {printf ("%d%lld\n",1,1); Continue; } Tol=0;        FINDFAC (n); Sort (Factor,factor+tol); Tot=0, num[tot]=1;  for(intI=1; i<tol;i++)        {            if(factor[i]==factor[i-1]) num[tot]++; Else{tot++; Num[tot]=1; }} tot++; intsum=Tol; intans1=Tol; Long LongAns2=1;  for(intI=0; i<tot;i++) {Ans2=ans2*C[sum][num[i]]; Sum=sum-Num[i]; } printf ("%d%lld\n", ANS1,ANS2); }    return 0;}

POJ 3421 X-factor Chains