From f1f2302acdfb4150c425269a5a4a48920c2be642 Mon Sep 17 00:00:00 2001
From: korzepadawid <korzepadawid@yahoo.com>
Date: Tue, 31 May 2022 21:34:31 +0200
Subject: [PATCH] counting islands with dfs

---
 algorithms/genetic/common.py        | 44 +++++++++++++++++++++++++++++
 algorithms/genetic/map_generator.py |  2 ++
 2 files changed, 46 insertions(+)

diff --git a/algorithms/genetic/common.py b/algorithms/genetic/common.py
index 9a4ed11..3f79021 100644
--- a/algorithms/genetic/common.py
+++ b/algorithms/genetic/common.py
@@ -1,7 +1,51 @@
 from dataclasses import dataclass
+from const import *
+from typing import List, Dict, Tuple
+
+import numpy.typing as npt
 
 
 @dataclass
 class Position:
     row: int
     col: int
+
+
+def dfs(grid: npt.NDArray, visited: Dict[Tuple[int, int], bool], position: Position, rows: int, cols: int) -> None:
+    visited[(position.row, position.col)] = True
+
+    row_vector = [0, 0, 1, -1]
+    col_vector = [-1, 1, 0, 0]
+
+    neighbours = []
+    for i in range(4):
+        rr = position.row + row_vector[i]
+        cc = position.col + col_vector[i]
+        if rr < 0 or rr >= ROWS:
+            continue
+        elif cc < 0 or cc >= COLUMNS:
+            continue
+        else:
+            p = Position(rr, cc)
+            if (p.row, p.col) in visited:
+                neighbours.append(p)
+
+    for neighbour in neighbours:
+        if not visited[(neighbour.row, neighbour.col)]:
+            dfs(grid, visited, neighbour, rows, cols)
+
+
+def count_islands(grid: npt.NDArray, positions: List[Position], rows: int = ROWS, cols: int = COLUMNS) -> int:
+    visited = {}
+
+    for position in positions:
+        visited[(position.row, position.col)] = False
+
+    islands = 0
+
+    for position in positions:
+        if not visited[(position.row, position.col)]:
+            dfs(grid, visited, position, rows, cols)
+            islands += 1
+
+    return islands
diff --git a/algorithms/genetic/map_generator.py b/algorithms/genetic/map_generator.py
index 3148352..060ebff 100644
--- a/algorithms/genetic/map_generator.py
+++ b/algorithms/genetic/map_generator.py
@@ -1,5 +1,6 @@
 from map_importer_exporter import export_map
 from genome import Genome
+from common import count_islands
 
 
 def main() -> None:
@@ -7,6 +8,7 @@ def main() -> None:
     print(example_genome.knights_red)
     print(example_genome.knights_blue)
     print(example_genome.grid)
+    print(count_islands(example_genome.grid, example_genome.sands + example_genome.waters))
     # export_map(example_genome.grid) fixme: FileNotFoundError
 
 
-- 
2.20.1