zoukankan      html  css  js  c++  java
  • [leetcode] Number of Islands

    Number of Islands

    Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

    Example 1:

    11110
    11010
    11000
    00000

    Answer: 1

    Example 2:

    11000
    11000
    00100
    00011

    Answer: 3

    Credits:
    Special thanks to @mithmatt for adding this problem and creating all test cases.
     
    分析: 对每次出现'1'的区域进行计数,同时深度或广度遍历,然后置为'x'。
    class Solution
    {
    private:
      void dfs(vector<vector<char> > &grid, int x, int y)
      {
        if(x < 0 || x >= grid.size()) return;
        if(y < 0 || y >= grid[0].size()) return;
        if(grid[x][y] != '1') return;
    
        grid[x][y] = 'x';
        dfs(grid, x-1, y);
        dfs(grid, x+1, y);
        dfs(grid, x, y-1);
        dfs(grid, x, y+1);
      }
    public:
      int numIslands(vector<vector<char> > &grid)
      {
        if(grid.empty() || grid[0].empty()) return 0;
        int X = grid.size(), Y = grid[0].size();
        int count = 0;
    
        for(int i=0; i<X; i++)
        {
          for(int j=0; j<Y; j++)
          {
            if(grid[i][j] == '1')
            {
              count++;
              dfs(grid, i, j);
            }
          }
        }
    
        return count;
      }
    };
  • 相关阅读:
    对软件工程的理解及问题
    使用Junit等工具进行单元测试
    软件工程
    进销存管理系统——可行性分析
    使用Junit等工具进行单元测试
    两个人的分组
    物联网软件工程 认识与问题
    二人项目
    使用Junit等工具进行单元测试
    软件工程
  • 原文地址:https://www.cnblogs.com/lxd2502/p/4481077.html
Copyright © 2011-2022 走看看