﻿ leetcode 200 : Number of Islands_今晚开什么码

# leetcode 200 : Number of Islands

## Leetcode 200 Number of Islands，leetcodeislands

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
``````

Example 2:

``````11000
11000
00100
00011
``````

``````def num_islands(grid)
return 0 if not grid
ans = 0
grid.length.times do |i|
grid.length.times do |j|
if grid[i][j] == '1'
ans += 1
extend(grid,i,j)
end
end
end
ans
end

def extend(grid,i,j)
if i<grid.length and j <grid.length and i>=0 and j>=0 and grid[i][j] == '1'
grid[i][j] = '0'
extend(grid,i+1,j)
extend(grid,i,j+1)
extend(grid,i-1,j)
extend(grid,i,j-1)
end
end
``````

200 Number of Islands，leetcodeislands 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...

### Number of Islands

Total Accepted: 8305 Total Submissions: 38192

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
``````

Example 2:

``````11000
11000
00100
00011
``````

[思路]

[CODE]

``````public class Solution {
public int numIslands(char[][] grid) {
int count = 0;
for(int i=0; i=grid.length || y<0 || y>=grid.length || grid[x][y]!='1') return;
grid[x][y] = '0';
search(grid, x-1, y);
search(grid, x+1, y);
search(grid, x, y-1);
search(grid, x, y+1);
}
}
``````

200 : Number of Islands Number of Islands Total Accepted: 8305 Total Submissions: 38192 Given a 2d grid map of 1 s (land) and 0 s (water), count the number of islands. An...