Day 17 - Number Of Islands

Solution.py

class Solution:
    def numIslands(self, grid: List[List[str]]) -> int:
        result = 0
        for row in range(len(grid)):
            for column in range(len(grid[0])):
                if grid[row][column] == '1':
                    result += 1
                    self.dfs(grid, row, column)
        return result
    
    def dfs(self, grid, row, column):
        grid[row][column] = '0'
        
        moves = [[0,1], [1,0], [-1,0], [0,-1]]
        
        for move in moves:
            newRow = row + move[0]
            newColumn = column + move[1]
            if self.isValidMove(grid, newRow, newColumn):
                self.dfs(grid, newRow, newColumn)
    
    def isValidMove(self, grid, r, c):
        if r >= len(grid) or c >= len(grid[0]) \
            or r < 0 or c < 0:
            return False
        
        if grid[r][c] == '0':
            return False
        
        return True