Add 2023 day 18

2023/day18.py

@@ -0,0 +1,153 @@
+#!/usr/bin/python3
+"""
+Jour 18 du défi Advent Of Code pour l'année 2023
+"""
+import os
+
+directions = {
+    "R": (0, 1),
+    "L": (0, -1),
+    "U": (-1, 0),
+    "D": (1, 0)
+}
+
+dir_col = ['R', 'D', 'L', 'U']
+
+def read_sample():
+    """récupère les entrées depuis le fichier texte correspondant"""
+    filename = os.path.join(os.path.dirname(__file__ ), "inputs", "day18.txt")
+    with open(filename, 'r') as f:
+        sample = f.read().split('\n')
+    sample = [ i for i in sample if i != '' ]
+    return sample
+
+
+def parse_sample(sample, new_method=False):
+    if new_method:
+        def parse_instr(c):
+            c = c.replace("(", '').replace(")", '')
+            dir_t = dir_col[int(c[-1])]
+            length = int(c[1:-1], 16)
+            return dir_t, length, c
+
+
+        return [parse_instr(c) for (a, b, c) in [j.split(" ") for j in sample]]
+    return [(a, int(b), c) for (a, b, c) in [j.split(" ") for j in sample]]
+
+
+def voisins(i, j):
+    return {(i+a, j+b) for (a, b) in directions.values()}
+
+
+def dig(data, only_edges=False):
+    terrain = []
+    pos = (0, 0)
+    for dir_t, length, color in data:
+        if only_edges:
+            terrain.append((pos, color))
+            pos = (pos[0]+directions[dir_t][0]*length, pos[1]+directions[dir_t][1]*length)
+        else:
+            for i in range(length):
+                terrain.append((pos, color))
+                pos = (pos[0]+directions[dir_t][0], pos[1]+directions[dir_t][1])
+
+    new_terrain = {t[0] for t in terrain}
+    min_x = min((i[1] for i in new_terrain))
+    min_y = min((i[0] for i in new_terrain))
+    return [((i-min_y, j-min_x), color) for ((i, j), color) in terrain]
+
+
+def count_holes(terrain):
+    new_terrain = {t[0] for t in terrain}
+    max_y = max((i[1] for i in new_terrain))+1
+    max_x = max((i[0] for i in new_terrain))+1
+
+    flow = set()
+
+    def has_hole(i, j):
+        cpt = 0
+        for k in range(j):
+            if (i, k) in new_terrain:
+                cpt += 1
+        if cpt == 1:
+            return True
+        return False
+
+    count = 0
+    for i in range(max_x):
+        for j in range(max_y):
+            if has_hole(i, j) and (i, j) not in new_terrain:
+                flow.add((i, j))
+
+    modif = True
+    while modif:
+        modif = False
+        for i in range(max_x):
+            for j in range(max_y):
+                if ((i, j) not in flow and len(voisins(i, j) & flow) > 0):
+                    if (i, j) not in new_terrain:
+                        modif = True
+                        flow.add((i, j))
+
+    #print_terrain({(i, '0') for i in flow|new_terrain})
+    return len(flow|new_terrain)
+
+
+def print_terrain(terrain):
+    new_terrain = {t[0] for t in terrain}
+    max_x = max((i[1] for i in new_terrain))
+    max_y = max((i[0] for i in new_terrain))
+
+    for i in range(max_y+1):
+        for j in range(max_x+1):
+            if (i, j) in new_terrain:
+                print('#', end='')
+            else:
+                print('.', end='')
+        print()
+
+
+def border(data):
+    return(sum((i[1] for i in data)))
+
+# https://www.tutorialspoint.com/program-to-find-area-of-a-polygon-in-python
+def getInfo(x1, y1, x2, y2):
+    return x1*y2 - y1*x2
+
+def solve(data):
+    points = [t[0] for t in data]
+    N = len(points)
+    firstx, firsty = points[0]
+    prevx, prevy = firstx, firsty
+    res = 0
+
+    for i in range(1, N):
+        nextx, nexty = points[i]
+        res = res + getInfo(prevx,prevy,nextx,nexty)
+        prevx = nextx
+        prevy = nexty
+    res = res + getInfo(prevx,prevy,firstx,firsty)
+    return abs(res)/2.0
+
+
+def part1(sample):
+    """Partie 1 du défi"""
+    data = parse_sample(sample, new_method=False)
+    terrain = dig(data)
+    return count_holes(terrain)
+
+def part2(sample):
+    """Partie 2 du défi"""
+    data = parse_sample(sample, new_method=True)
+    terrain = dig(data, only_edges=True)
+    return int(solve(terrain)+border(data)//2 +1)
+
+
+def main():
+    """Fonction principale"""
+    sample = read_sample()
+    print(f"part1: {part1(sample)}")
+    print(f"part2: {part2(sample)}")
+
+if __name__ == "__main__":
+    main()