Day 5

day5.py

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+import numpy as np
+
+"""
+Advent of Code 2022 - Day 5
+
+Notes:
+wow, lot of code this time. Parsing could be cut down quite ab it using divisions of the line length,
+and later with regex. Probably worth praciticing regex more. Faster solutions used a lot of clever slicing
+too.
+
+Def need to work on more compact parsing, this would be good input data for practice
+
+Time taken: ~20 min
+
+"""
+
+with open("day5.txt", "r") as file:
+    inp = file.read().split("\n")
+
+def getLetters(line):
+    """
+    From a line, extract the letters from the line
+    returns in format ["", "", "", "A", "B"], where "" are empty spots
+    
+    """
+    letters = []
+    spl = line.replace("    ", "-").replace(" ", "-").split("-")
+    for item in spl:
+        if item == "":
+            letters.append("")
+        elif item[0] == "[":
+            letters.append(item[1])
+        else:
+            pass
+    return letters
+
+
+table = []
+inst_index = 0
+for i, line in enumerate(inp):
+    table.append(getLetters(line)) #append to table the letters 
+    if len(line) == 0: #check for when weve reached the end of the table
+        del table[-1] #and remove the extra entries
+        del table[-1]
+        inst_index = i+1 #record the index the instructions begin 
+        break
+
+table = np.transpose(table) #transpose to get it to be a list of stacks
+stacks = [] # here I realized how convienent stack data structures would be, so quick  
+            # reorganization of data into stacks without blank spaces
+            # would've been better to do this from the start but oh well
+for i, stack in enumerate(table):
+    stacks.append([])
+    for item in stack:
+        if item != "":
+            stacks[i].append(item)
+    stacks[i].reverse() #since we append from top down, reverse so our top elements are at the 
+                        #end of the stack
+
+#part 2
+def makeMove_p2(n, s1, s2): #make a move, move n crates from s1 to s2, order maintained
+    int_stack = []
+    for i in range(0, n):
+        int_stack.append(stacks[s1-1].pop())
+    for i in range(0, n):
+        stacks[s2-1].append(int_stack.pop())
+
+#part 1
+def makeMove_p1(n, s1, s2): #make a move, move n crates from s1 to s2, order not maintaned
+    for i in range(0, n):
+        stacks[s2-1].append(stacks[s1-1].pop())
+
+
+for i in range(inst_index, len(inp)): #carry out move for each instruction
+    line = inp[i]
+    line = line.split(" ")
+    n =  int(line[1] )
+    s1 = int(line[3])
+    s2 = int(line[5])
+
+    makeMove_p2(n, s1, s2)
+
+#print top item for each stack
+for stack in stacks:
+    print(stack.pop(), end="")
+
+
+