biggest_and_smallest_island.js

var assert = require('assert')

/**
 * @param {character[][]} grid
 * @return {number}
 */
var numIslands = function(grid) {
    var count = 0
    var max = -Infinity
    var min = Infinity
    for(var i = 0; i < grid.length; i++){
        for(var j = 0; j < grid[0].length; j++){
            if(grid[i][j] === '1'){
                count++
                var n = bfs(grid, i, j)
                console.log(n)
                max = Math.max(max, n)
                min = Math.min(min, n)
            }
        }
    }
    return [max, min]
};

function bfs(grid, x, y){
    var queue = []
    var number = 0
    grid[x][y] = '2'
    queue.push([x,y])
    while(queue.length > 0){
        var node = queue.shift()
        number++
        var _x = node[0]
        var _y = node[1]
        
        if(helper(grid, _x + 1, _y)) queue.push([_x + 1, _y])
        if(helper(grid, _x - 1, _y)) queue.push([_x - 1, _y])
        if(helper(grid, _x, _y + 1)) queue.push([_x, _y + 1])
        if(helper(grid, _x, _y - 1)) queue.push([_x, _y - 1])
    }
    return number
}

function helper(grid, x, y){
  if(grid[x] === undefined || grid[x][y] === undefined) return false
  if(grid[x][y] !== '1') return false
  grid[x][y] = '2'
  return true
}

var input = [
  ['1','1','0','0','0'],
  ['1','1','0','1','0'],
  ['1','1','0','0','0'],
  ['0','0','0','0','0']]

assert.deepEqual(numIslands(input), [6, 1])

var assert = require('assert')

/**
 * @param {character[][]} grid
 * @return {number}
 */
var numIslands = function(grid) {
    var count = 0
    var max = -Infinity
    var min = Infinity
    for(var i = 0; i < grid.length; i++){
        for(var j = 0; j < grid[0].length; j++){
            if(grid[i][j] === '1'){
                count++
                var n = dfs(grid, i, j, 0)
                console.log(n)
                max = Math.max(max, n)
                min = Math.min(min, n)
            }
        }
    }
    return [max, min]
};

function dfs(grid, i, j){
  
  if(grid[i] === undefined || grid[i][j] === undefined) return 0
  if(grid[i][j] !== '1') return 0
  grid[i][j] = '2'
  
  return(
  dfs(grid, i+1, j) +
  dfs(grid, i-1, j) +
  dfs(grid, i, j+1) +
  dfs(grid, i, j-1) + 1)
}

var input = [
  ['1','1','0','0','0'],
  ['1','1','0','1','0'],
  ['1','1','0','0','0'],
  ['0','0','0','0','0']]

assert.deepEqual(numIslands(input), [6, 1])