poj 3414 pots (bfs+路径记录)

Pots
Time Limit: 1000MS   Memory Limit: 65536K
Total Submissions: 11703   Accepted: 4955   Special Judge

Description

You are given two pots, having the volume of A and B liters respectively. The following operations can be performed:

  1. FILL(i)        fill the pot i (1 ≤ ≤ 2) from the tap;
  2. DROP(i)      empty the pot i to the drain;
  3. POUR(i,j)    pour from pot i to pot j; after this operation either the pot j is full (and there may be some water left in the pot i), or the pot i is empty (and all its contents have been moved to the pot j).

Write a program to find the shortest possible sequence of these operations that will yield exactly C liters of water in one of the pots.

Input

On the first and only line are the numbers AB, and C. These are all integers in the range from 1 to 100 and C≤max(A,B).

Output

The first line of the output must contain the length of the sequence of operations K. The following K lines must each describe one operation. If there are several sequences of minimal length, output any one of them. If the desired result can’t be achieved, the first and only line of the file must contain the word ‘impossible’.

Sample Input

Sample Output

 

 

好爽,一遍ac

poj 3984 迷宫问题

迷宫问题
Time Limit: 1000MS   Memory Limit: 65536K
Total Submissions: 10967   Accepted: 6547

Description

定义一个二维数组: 


它表示一个迷宫,其中的1表示墙壁,0表示可以走的路,只能横着走或竖着走,不能斜着走,要求编程序找出从左上角到右下角的最短路线。

Input

一个5 × 5的二维数组,表示一个迷宫。数据保证有唯一解。

Output

左上角到右下角的最短路径,格式如样例所示。

Sample Input

Sample Output