summertime warmup session with 2020 event

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diff --git a/2020/aoc2020-d10.py b/2020/aoc2020-d10.py
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+#advent of code 2020
+#day 10
+#very similar (if not identical) to towels puzzle, 2024-d19
+#memorize previous paths and just sum up the valid paths for each adapter
+#although this one i think is easier due to no duplicates 
+#and working on numbers instead of characters
+bag = [];
+PuzzleInput = open("10.in","r");
+for num in PuzzleInput: bag.append(int(num));
+PuzzleInput.close();
+#first and last items are from puzzle description
+bag = [0] + [x for x in sorted(bag)] + [max(bag) +3]; 
+connections = dict();
+connections[1] = 0;
+connections[2] = 0;
+connections[3] = 0;
+#since there are no duplicates and all adapters must be connected
+#we can just check against the previous value for part 1;
+for index in range(1,len(bag)):
+	adapter1 = bag[index];
+	adapter2 = bag[index-1];	
+	diff = adapter1 - adapter2;
+	connections[diff] += 1;
+
+p1 = connections[1] * connections[3];
+
+p2 = 0;
+options = dict();
+options[0] = 1;
+for index in range(1,len(bag)):	
+	previous = bag[:index];
+	possible = [x for x in previous if bag[index] - x <=3];
+	options[bag[index]] = 0;
+	for poss in possible:
+		options[bag[index]] += options[poss];	
+
+p2 = options[max(bag)];
+print("part 1 =",p1);
+print("part 2 =",p2);