Add solution for day 9

AoC2021/code/AoC09.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import sys
+
+def risk_level(m, x, y):
+    adj = []
+    if x-1 > -1:
+        adj.append(m[x-1][y])
+    try: adj.append(m[x+1][y])
+    except IndexError: pass
+    if y-1 > -1:
+        adj.append(m[x][y-1])
+    try: adj.append(m[x][y+1])
+    except IndexError: pass
+
+    for a in adj:
+        if a <= m[x][y]:
+            return 0
+    return m[x][y] + 1
+
+def basin(m, x, y):
+    while (x,y) not in bas:
+        adj = {}
+        adj[(0,0)] = m[x][y]
+        if x-1 > -1:
+            adj[(-1,0)] = m[x-1][y]
+        try: adj[(1,0)] = m[x+1][y]
+        except IndexError: pass
+        if y-1 > -1:
+            adj[(0,-1)] = m[x][y-1]
+        try: adj[(0,1)] = m[x][y+1]
+        except IndexError: pass
+        
+        mi = min(adj.items(),key=lambda x: x[1])
+        
+        x += mi[0][0]
+        y += mi[0][1]
+    bas[(x,y)] += 1
+    
+
+if __name__ == '__main__':
+    lines = open(sys.argv[1]).read().strip('\n\n').split('\n') # or split \n\n or sth similar
+    mp = [[int(i) for i in l] for l in lines]
+    
+    bas = {}
+    risk = 0
+    for x in range(len(mp)):
+        for y in range(len(mp[0])):
+            r = risk_level(mp, x, y)
+            risk += r
+            if r > 0:
+                bas[(x,y)] = 0
+
+    
+    for x in range(len(mp)):
+        for y in range(len(mp[0])):
+            if mp[x][y] != 9:
+                basin(mp, x, y)
+
+    b = sorted(bas.values(), reverse=True)
+
+    # challenge 1
+    res1 = str(risk)
+    print("challenge 1:" +"\n" +  res1 + "\n")
+
+    # challenge 2
+
+    res2 = str(b[0]*b[1]*b[2])
+    print("challenge 2:" +"\n" +  res2 + "\n")
+