Day 9 solution !

2020/day_9/encoding_error.py

@@ -0,0 +1,30 @@
+def is_sum(number, series):
+    for i in series:
+        if (number - i) in series:
+            return True
+    return False
+
+def find_contiguous_sum(number, series):
+    for i in range(0, len(series)):
+        for j in range(i, len(series)):
+            if sum(series[i:j + 1]) == number:
+                return series[i:j+1]
+
+
+def solve_a(data, length):
+    for i in range(length, len(data)):
+        number = data[i]
+        if not is_sum(number, data[i - length:i]):
+            return number
+
+def solve_b(number, data):
+    series = find_contiguous_sum(number, data)
+    series.sort()
+    return series[0] + series[-1]
+
+data = [int(line.strip()) for line in open('input')]
+
+result = solve_a(data, 25)
+print(result)
+print(solve_b(result, data))
+