Codeforces Perfect Pair (JAVA)

http://codeforces.com/problemset/problem/317/A

题意：给两个数字，可以两数相加去替换其中一个数字。问要做多少次，可以让两个数字钟至少一个 >= 目标数字m，输出次数，不可能的话输出-1

比较简单的题目，用来练习JAVA，代码写得有点，呵呵................

 

import java.util.*;



public class Main{

   

  static long max(long x , long y){

      return x > y ? x : y;

  }

  

  static long solve(long a ,long b ,long c){

      long res = 0;

      while( (a >= c || b >= c) == false){

          long sum = a + b;

          long Max = max(a , b);

          a = sum; b = Max;

          res++;

      }

      return res;

  }

  static long __solve(long a , long b , long c){

      long res = (-b + a - 1) / a;

      long tmp = b + res * a;

      res += solve(a,tmp,c);

      return res;

  }

  

  public static void main(String[] args){

      Scanner cin = new Scanner(System.in);

      long a,b,c,res;

      a = cin.nextLong();

      b = cin.nextLong();

      c = cin.nextLong();

      if(a >= c || b >= c)

          res = 0;

      else if(a <= 0 && b <= 0)

          res = -1;

      else if(a >= 0 && b >= 0){

          res = solve(a,b,c);

      }

      else{

          long tmp;

          if(a < b){

              tmp = a; a = b; b = tmp;

          }

          res = __solve(a,b,c);

      }

      

      System.out.println(res);

  }

}