TopCoder 練習

CarrotJumping(Member SRM 478 Div1 Easy)

import java.util.*;
import java.math.*;
import java.lang.*;

public class CarrotJumping{
 public int theJump(int init){
  long r=4;
  int n;
  for(n=2;n<=300000;n++){
   if((r*init+r-1)%1000000007L==0)
    break;
   r*=2;
   r%=1000000007L;
  }
  int ans=(n+2)/3;
  if(ans>100000)
   return -1;
  else return ans;
 }
}