Add day 8 solution

08/example

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+

08/trees.py

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+
+import fileinput
+
+def get_row(m, idx):
+    return m[idx]
+
+def get_col(m, idx):
+    return list(map(lambda x: x[idx], m))
+
+class Forest:
+
+    def __init__(self, width, height):
+        self.visible = []
+        self.heightmap = []
+        self.score = []
+        self.width = width
+        for _ in range(height):
+            self.visible.append([False] * width)
+            self.heightmap.append([0] * width)
+            self.score.append([0] * width)
+
+    def print(self):
+        print("Heightmap:")
+        for r in self.heightmap:
+            print(''.join(map(lambda x: str(x), r)))
+        print("Visibility:")
+        for r in self.visible:
+            print(''.join(map(lambda x: "X" if x else "O", r)))
+    
+    def solve_visibility(self):
+        # TOP-DOWN
+        limit = [-1] * self.width
+        for rowidx in range(self.width):
+            for colidx in range(self.width):
+                if limit[colidx] < self.heightmap[rowidx][colidx]:
+                    self.visible[rowidx][colidx] = True
+                    limit[colidx] = self.heightmap[rowidx][colidx]
+
+        # BOT-UP
+        limit = [-1] * self.width
+        for rowidx in range(self.width):
+            for colidx in range(self.width):
+                if limit[colidx] < self.heightmap[-rowidx-1][colidx]:
+                    self.visible[-rowidx-1][colidx] = True
+                    limit[colidx] = self.heightmap[-rowidx-1][colidx]
+
+        # LEFT-RIGHT
+        limit = [-1] * self.width
+        for colidx in range(self.width):
+            for rowidx in range(self.width):
+                if limit[rowidx] < self.heightmap[rowidx][colidx]:
+                    self.visible[rowidx][colidx] = True
+                    limit[rowidx] = self.heightmap[rowidx][colidx]
+
+        # RIGHT-LEFT
+        limit = [-1] * self.width
+        for colidx in range(self.width):
+            for rowidx in range(self.width):
+                if limit[rowidx] < self.heightmap[rowidx][-colidx-1]:
+                    self.visible[rowidx][-colidx-1] = True
+                    limit[rowidx] = self.heightmap[rowidx][-colidx-1]
+        
+    def solve_score(self):
+        for rowidx in range(self.width):
+            for colidx in range(self.width):
+                current = self.heightmap[rowidx][colidx]
+                lscore = 0
+                rscore = 0
+                uscore = 0
+                dscore = 0
+                for idx in range(colidx): # left
+                    lscore += 1
+                    if self.heightmap[rowidx][colidx-idx-1] >= current:
+                        break
+                for idx in range(self.width - colidx - 1): # right
+                    rscore += 1
+                    if self.heightmap[rowidx][colidx+idx+1] >= current:
+                        break
+                for idx in range(rowidx): # up
+                    uscore += 1
+                    if self.heightmap[rowidx-idx-1][colidx] >= current:
+                        break
+                for idx in range(self.width - rowidx - 1): # down
+                    dscore += 1
+                    if self.heightmap[rowidx+idx+1][colidx] >= current:
+                        break
+                self.score[rowidx][colidx] = lscore*rscore*uscore*dscore
+    
+    @classmethod
+    def parse(cls, lines):
+        output = None
+        idx = 0
+        for line in map(lambda x: x.strip(), lines):
+            if line != "":
+                if output is None:
+                    output = cls(len(line), len(line))
+                output.heightmap[idx] = list(map(lambda x: int(x), list(line)))
+                idx += 1
+        return output
+
+    def visible_count(self):
+        output = 0
+        for r in self.visible:
+            output += sum(r)
+        return output
+
+if __name__ == "__main__":
+    forest = Forest.parse(fileinput.input())
+    forest.solve_visibility()
+    forest.solve_score()
+    forest.print()
+    print(f"Visible: {forest.visible_count()}")
+    print(f"Score: {max([max(row) for row in forest.score])}")