poj 2369 Permutations

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#include<cstring>
#include<vector>
#include<string>
#define LL long long
using namespace std;
int Gcd( int a , int b )
{
return b == 0? a : Gcd( b , a % b );
}
int Solve( int N , int num[] )
{
int ans = 1;
bool visit[1024] = { 0 };
for( int i = 1; i <= N; i ++ )
{
if( !visit[i] )
{
visit[i] = true;
int t = num[i],cnt=1;
while( i != t )
{
visit[t] = true;
cnt ++;
t = num[t];
}
ans = (ans/Gcd( ans , cnt ))*cnt;
}
}
return ans;
}
int main(  )
{
int num[1024],N;
while( scanf( "%d",&N )==1 )
{
for( int i = 1 ; i <= N ; i ++ )
{
scanf( "%d",&num[i] );
}
printf( "%d\n",Solve( N ,num ) );
}
//system( "pause" );
return 0;
}