题目

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

Example 2:

11000

思路

可以参考：

代码

/*------------------------------------------------------*   日期：2014-04-10*   作者：SJF0115*   题目: 200.Number of Islands*   网址：https://leetcode.com/problems/number-of-islands/*   结果：AC*   来源：LeetCode*   博客：--------------------------------------------------------*/#include 
     
      #include 
      
       using namespace std;class Solution {public:    int numIslands(vector
       
        
         > &grid) {        // 行数        int row = grid.size();        if(row == 0){            return 0;        }//if        // 列数        int col = grid[0].size();        if(col == 0){            return 0;        }//if        int count = 0;        for(int i = 0;i < row;++i){            for(int j = 0;j < col;++j){                // 如果是1且没有被访问过则发现一个新的岛屿                if(grid[i][j] == '1'){                    // 以该岛屿做深度遍历                    DFS(grid,row,col,i,j);                    ++count;                }//if            }//for        }//for        return count;    }private:    // grid 地图 row 行数 col 列数 (x,y)当前坐标    void DFS(vector
         
          
            > &grid,int row,int col,int x,int y){ if(x < 0 || y < 0 || x >= row || y >= col || grid[x][y] == '0'){ return; }//if grid[x][y] = '0'; // right DFS(grid,row,col,x,y+1); // left DFS(grid,row,col,x,y-1); // top DFS(grid,row,col,x-1,y); // bottom DFS(grid,row,col,x+1,y); }};int main() { Solution solution; vector
           
            
              > grid = { { '1', '1', '0', '0', '0'}, { '1', '1', '0', '0', '0'}, { '0', '0', '1', '0', '0'}, { '0', '0', '0', '1', '1'} }; cout<
             
              <
             
            
           
          
         
        
       
      
     

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