script to evaluate day 5 problem paths

nix/evaluate-path/default.nix

@@ -0,0 +1,18 @@
+{ lib
+, python3Packages
+}:
+
+python3Packages.buildPythonApplication rec {
+  pname = "evaluate-path";
+  version = "1.0.0";
+
+  format = "other";
+
+  src = ./.;
+
+  installPhase = ''
+    install -Dm755 $src/evaluate-path.py $out/bin/evaluate-path
+  '';
+
+  doCheck = false;
+}

nix/evaluate-path/evaluate-path.py

@@ -0,0 +1,133 @@
+#! /usr/bin/env python3
+
+import sys
+import argparse
+from copy import deepcopy
+from queue import deque
+
+def shortest_path_length(graph):
+    q = deque([(0, 0, 0)])
+    visited = set()
+
+    while q:
+        i, j, length = q.popleft()
+
+        if i == len(graph)-1 and j == len(graph[-1])-1:
+            return length
+
+        if (i, j) in visited:
+            continue
+
+        visited.add((i, j))
+
+        for di, dj in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
+            ni = i + di
+            nj = j + dj
+            if 0 <= ni < len(graph) and 0 <= nj < len(graph[ni]) and (ni, nj) not in visited:
+                q.append((ni, nj, length + 1))
+
+    return -1
+
+def evaluate_path(graph, path):
+    if len(graph) == 0 or len(graph[0]) == 0:
+        print("❓ Empty graph", file=sys.stderr)
+        return False, graph
+
+    expected_length = shortest_path_length(graph)
+    if expected_length == -1:
+        print("❗ There is no path from top left to bottom right in this graph")
+    if len(path) < expected_length:
+        print(f"❕ Path is too short (expected {expected_length} but got {len(path)})")
+    elif len(path) > expected_length:
+        print(f"❕ Path is too long (expected {expected_length} but got {len(path)})")
+
+    out_graph = deepcopy(graph)
+    i = 0
+    j = 0
+    if graph[i][j] == '#':
+        out_graph[i][j] = 'T'
+    else:
+        out_graph[i][j] = 'X'
+        print(f"🤯 Timmy falls into the water at spawn ({i}, {j})")
+        return False, out_graph
+
+    for direction in path:
+        if direction == 'R':
+            j += 1
+        elif direction == 'D':
+            i += 1
+        elif direction == 'L':
+            j -= 1
+        elif direction == 'U':
+            i -= 1
+
+        if i < 0 or i >= len(graph) or j < 0 or j >= len(graph[i]):
+            print(f"😱 Timmy falls out of bounds at coordinnates ({i}, {j})")
+            return False, out_graph
+
+        if graph[i][j] == '#':
+            out_graph[i][j] = 'T'
+        else:
+            out_graph[i][j] = 'X'
+            print(f"🥶 Timmy falls into the water at coordinnates ({i}, {j})")
+            return False, out_graph
+
+    result = False
+    if i == len(graph)-1 and j == len(graph[-1])-1:
+        result = True
+
+    return result, out_graph
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        prog="evaluate_path",
+        description="Test if a path is valid for the given input for the 5th problem")
+    parser.add_argument(
+        "INPUT_FILE", help="input file, the graph to test the path on", action="store", type=str)
+    parser.add_argument(
+        "PATH_FILE", help="path file, the path to evaluate", action="store", type=str)
+    parser.add_argument(
+        "OUTPUT_FILE", help="output file, file to write the out-graph with the path displayed to (T for valid squares, X for invalid squares)",
+        action="store", type=str, nargs="?")
+
+    args = parser.parse_args()
+    INPUT_FILE = args.INPUT_FILE
+    PATH_FILE = args.PATH_FILE
+    OUTPUT_FILE = args.OUTPUT_FILE
+
+    try:
+        inputfile = open(INPUT_FILE, "r")
+    except (OSError, IOError):
+        print(f"Error: {INPUT_FILE}: cannot read input file", file=sys.stderr)
+        exit(1)
+
+    try:
+        pathfile = open(PATH_FILE, "r")
+    except (OSError, IOError):
+        print(f"Error: {PATH_FILE}: cannot read path file", file=sys.stderr)
+        exit(1)
+
+    graph = [list(line[:-1]) for line in inputfile.readlines()]
+    path = [line[:-1] for line in pathfile.readlines()]
+
+    result, out_graph = evaluate_path(graph, path)
+
+    if result:
+        print("✅ Valid path")
+    else:
+        print("❌ Invalid path")
+
+
+    if OUTPUT_FILE:
+        try:
+            outfile = open(OUTPUT_FILE, "w")
+        except (OSError, IOError):
+            print(f"Error: {OUTPUT_FILE}: cannot open output file", file=sys.stderr)
+            exit(1)
+
+        for line in out_graph:
+            outfile.write("".join(line))
+            outfile.write("\n")
+
+        print(f"🗺️  Wrote out-graph to {OUTPUT_FILE}")

nix/shell.nix

@@ -4,5 +4,6 @@
       python3
       (pkgs.callPackage ./05AB1E { })
       (pkgs.callPackage ./05AB1E-encode { })
+      (pkgs.callPackage ./evaluate-path { })
     ];
 }