Created
October 12, 2019 11:28
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Google Coding Interviews Number of Islands (LeetCode) and explanation. One of Google's most commonly asked interview questions according to LeetCode. This coding interview question is commonly asked by companies like: Google, Facebook, Snapchat, Amazon, Uber, LinkedIn, Microsoft, Apple and many others.
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/** | |
* @param {character[][]} grid | |
* @return {number} | |
*/ | |
var dfs = function(grid, i, j) { | |
const w = grid.length; | |
const h = grid[0].length; | |
if ( i >= 0 && i < w && j >= 0 && j < h && grid[i][j] == '1') { | |
grid[i][j] = '0' | |
dfs(grid, i+1, j); //right | |
dfs(grid, i-1, j); //left | |
dfs(grid, i, j+1); //below | |
dfs(grid, i, j-1); //above | |
} | |
} | |
var numIslands = function(grid) { | |
let islands = 0; | |
if(grid.length == 0) { | |
return 0; | |
} | |
const w = grid.length; | |
const h = grid[0].length; | |
for (let i=0; i<w; i++) { | |
for(let j=0; j<h; j++) { | |
const char = grid[i][j]; | |
if (char == '1') { | |
dfs(grid, i, j); | |
islands += 1; | |
} | |
} | |
} | |
return islands; | |
}; |
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