Add day4 problem + solution

day4/p1.nim

@@ -0,0 +1,78 @@
+import os
+import std/[strutils, sets, sequtils]
+
+proc didColumnWin(board: seq[int], size: int, col: int, calledNumbers: HashSet[int]): bool =
+  for i in 0 ..< size:
+    let el = board[col + i*size]
+    if not calledNumbers.contains(el):
+      return false
+
+  return true
+
+proc didRowWin(board: seq[int], size: int, row: int, calledNumbers: HashSet[int]): bool =
+
+  for i in 0 ..< size:
+    if not calledNumbers.contains(board[row*size + i]):
+      return false
+
+  return true
+
+
+proc didBoardWin(board: seq[int], size: int, calledNumbers: HashSet[int]): bool =
+  for i in 0 ..< size:
+    if didRowWin(board, size, i, calledNumbers):
+      return true
+
+    if didColumnWin(board, size, i, calledNumbers):
+      return true
+
+
+proc main() =
+  let
+    fileName = paramStr(1)
+    file = open(fileName, fmRead)
+    allNumbers = toSeq(file.readLine().split(",").mapIt(it.parseInt))
+
+  discard file.readLine() # skip blank line
+
+  var boards: seq[seq[int]]
+  boards.add(newSeq[int]())
+
+  var
+    boardIndex = 0
+    boardSize = 0
+
+  while not file.endOfFile():
+    let line = file.readLine()
+
+    if line.strip() == "":
+      boards.add(newSeq[int]())
+      boardIndex += 1
+    else:
+      let board = line.strip().splitWhitespace().mapIt(it.parseInt)
+      boardSize = board.len
+      boards[boardIndex].add(board)
+
+
+  var
+    currentNumbers: HashSet[int]
+    index = 0
+
+  while len(currentNumbers) < len(allNumbers):
+    let num = allNumbers[index]
+
+    currentNumbers.incl(num)
+
+    for board in boards:
+      if didBoardWin(board, boardSize, currentNumbers):
+        let
+          unmarked = toHashSet(board) - currentNumbers
+          sum = unmarked.toSeq.foldl(a + b)
+        echo "Winner: ", board
+        echo "Score: ", sum*num
+        return
+
+    index += 1
+
+
+main()