1、Google 编程大赛入围赛 750 分真题 第五组Problem Statement牋牋You are given a String grid representing a rectangular grid of letters. You are also given a String find, a word you are to find within the grid. The starting point may be anywhere in the grid. The path may move up, down, left, right, or diagonally from o
2、ne letter to the next, and may use letters in the grid more than once, but you may not stay on the same cell twice in a row (see example 6 for clarification). You are to return an int indicating the number of ways find can be found within the grid. If the result is more than 1,000,000,000, return -1
3、. Definition牋牋Class:WordPathMethod:countPathsParameters:String, StringReturns:intMethod signature:int countPaths(String grid, String find)(be sure your method is public)牋牋Constraints-grid will contain between 1 and 50 elements, inclusive.-Each element of grid will contain between 1 and 50 uppercase
4、(A-Z) letters, inclusive.-Each element of grid will contain the same number of characters.-find will contain between 1 and 50 uppercase (A-Z) letters, inclusive.Examples0)牋牋“ABC“,“FED“,“GHI“ABCDEFGHI“Returns: 1There is only one way to trace this path. Each letter is used exactly once.1)牋牋“ABC“,“FED“
5、,“GAI“ABCDEA“Returns: 2Once we get to the E, we can choose one of two directions for the final A.2)牋牋“ABC“,“DEF“,“GHI“ABCD“Returns: 0We can trace a path for “ABC“, but theres no way to complete a path to the letter D.3)牋牋“AA“,“AA“AAAA“Returns: 108We can start from any of the four locations. From eac
6、h location, we can then move in any of the three possible directions for our second letter, and again for the third and fourth letter. 4 * 3 * 3 * 3 = 108. 4)牋牋“ABABA“,“BABAB“,“ABABA“,“BABAB“,“ABABA“ABABABBA“Returns: 56448There are a lot of ways to trace this path.5)牋牋“AAAAA“,“AAAAA“,“AAAAA“,“AAAAA“
7、,“AAAAA“AAAAAAAAAAA“Returns: -1There are well over 1,000,000,000 paths that can be traced.6)牋牋“AB“,“CD“AA“Returns: 0Since we cant stay on the same cell, we cant trace the path at all.This problem statement is the exclusive and proprietary property of TopCoder, Inc. Any unauthorized use or reproduction of this information without the prior written consent of TopCoder, Inc. is strictly prohibited. (c)2003, TopCoder, Inc. All rights reserved.
