zoukankan      html  css  js  c++  java
  • leetcode------Word Search

    标题: Word Search
    通过率: 20.0%
    难度: 中等

    Given a 2D board and a word, find if the word exists in the grid.

    The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once.

    For example,
    Given board =

    [
      ["ABCE"],
      ["SFCS"],
      ["ADEE"]
    ]
    

    word = "ABCCED", -> returns true,
    word = "SEE", -> returns true,
    word = "ABCB", -> returns false.

    需要尝试从每一个位置起开始遍历,每次向四个方向开始遍历,如果四个方向都不满足时要将走过的路径回复,边界问题看代码:

    用一个index记录查了多少个了。

    迭代算法依然没有知道突破口:

     1 public class Solution {
     2     private int m,n;
     3     public boolean exist(char[][] board, String word) {
     4         m=board.length;
     5         n=board[0].length;
     6         boolean [][] visted=new boolean[m][n];
     7         for(int i=0;i<m;i++)
     8         for(int j=0;j<n;j++){
     9             if(dfs(board,word,0,i,j,visted))
    10                 return true;
    11         }
    12         return false;
    13     }
    14     public boolean dfs(char[][] board, String word,int index,int startx,int starty,boolean [][] visted){
    15         if(index==word.length())return true;
    16         if(startx<0||startx>=m||starty<0||starty>=n)return false;
    17         if(visted[startx][starty])return false;
    18         if(board[startx][starty]!=word.charAt(index))return false;
    19         visted[startx][starty]=true;
    20         boolean res=dfs(board,word,index+1,startx+1,starty,visted)||dfs(board,word,index+1,startx-1,starty,visted)||dfs(board,word,index+1,startx,starty+1,visted)||dfs(board,word,index+1,startx,starty-1,visted);
    21         visted[startx][starty]=false;
    22         return res;
    23     }
    24 }
  • 相关阅读:
    iOS:不同属性声明方式的解析
    iOS:图像和点击事件
    iOS:NAV+TABLE结合
    iOS:实现表格填充和选择操作
    iOS: 填充数据表格
    iOS:导航栏的工具条和导航条
    iOS:使用导航栏
    hello,world不使用ARC
    iOS代码实现:创建按钮,绑定按钮事件,读取控件值
    iOS版 hello,world版本2
  • 原文地址:https://www.cnblogs.com/pkuYang/p/4349936.html
Copyright © 2011-2022 走看看