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39 lines (35 loc) · 912 Bytes
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NumberOfIslands.java
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39 lines (35 loc) · 912 Bytes
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package Recursion;
/*
200. Number of Islands
*/
public class NumberOfIslands {
public int numIslands(char[][] grid) {
int islands = 0;
if(grid.length==0) return islands;
for(int i=0; i< grid.length;i++){
for(int j =0; j< grid[0].length;j++){
if(grid[i][j]=='1'){
dfs(grid,i,j);
islands++;
}
}
}
return islands;
}
public void dfs(char[][]grid, int i , int j){
if (
i < 0 ||
j < 0 ||
i >= grid.length ||
j >= grid[0].length ||
grid[i][j] == '0'
) {
return;
}
grid[i][j] = '0';
dfs(grid, i + 1, j);
dfs(grid, i, j + 1);
dfs(grid, i - 1, j);
dfs(grid, i, j - 1);
}
}