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Add number of islands

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Kayla
2020-10-01 21:50:05 -04:00
parent e3ee2b2675
commit b06aa8733f
1 changed files with 21 additions and 20 deletions
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41
Graphs/NumberOfIslands.js
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@ -1,4 +1,5 @@
/* Number of Islands /* Number of Islands
https://dev.to/rattanakchea/amazons-interview-question-count-island-21h6
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. 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.
two a dimensial grid map two a dimensial grid map
@ -49,37 +50,37 @@ const grid = [
['1', '1', '0', '0', '0'], ['1', '1', '0', '0', '0'],
['1', '1', '0', '0', '0'], ['1', '1', '0', '0', '0'],
['0', '0', '1', '0', '0'], ['0', '0', '1', '0', '0'],
['0', '0', '0', '1', '1'], ['0', '0', '0', '1', '1']
]; ]
const islands = (matrixGrid) => { const islands = (matrixGrid) => {
const matrix = matrixGrid; const matrix = matrixGrid
let counter = 0; let counter = 0
const flood = (row, col) => { const flood = (row, col) => {
if (row < 0 || col < 0) return; // Off the map above or left if (row < 0 || col < 0) return // Off the map above or left
if (row >= matrix.length || col >= matrix[row].length) return; // Off the map below or right if (row >= matrix.length || col >= matrix[row].length) return // Off the map below or right
const tile = matrix[row][col]; const tile = matrix[row][col]
if (tile !== '1') return; if (tile !== '1') return
matrix[row][col] = '0'; matrix[row][col] = '0'
flood(row + 1, col); // Down flood(row + 1, col) // Down
flood(row - 1, col); // Up flood(row - 1, col) // Up
flood(row, col + 1); // Right flood(row, col + 1) // Right
flood(row, col - 1); // Left flood(row, col - 1) // Left
}; }
for (let row = 0; row < matrix.length; row += 1) { for (let row = 0; row < matrix.length; row += 1) {
for (let col = 0; col < matrix[row].length; col += 1) { for (let col = 0; col < matrix[row].length; col += 1) {
const current = matrix[row][col]; const current = matrix[row][col]
if (current === '1') { if (current === '1') {
flood(row, col); flood(row, col)
counter += 1; counter += 1
} }
} }
} }
return counter; return counter
}; }
console.log(islands(grid))