adventofcode-2023/day_03/solution_03.nim

import std/[cmdline, sequtils, strformat, strutils, sugar]

proc isAdjacentToCond(grid: seq[seq[char]], row, col: int, cond: (char) -> bool): bool =
    for i in @[row - 1, row, row + 1]:
        if i < 0 or i >= grid.len:
            continue
        for j in @[col - 1, col, col + 1]:
            if i == row and j == col:
                continue
            if j < 0 or j >= grid[i].len:
                continue
            var ch = grid[i][j]
            if cond(ch):
                return true
    return false


var fn = if paramCount() > 0: paramStr(1) else: "input_03.txt"

var result = 0
var lines = readFile(fn).strip.splitLines
var grid = newSeqWith(lines.len, newSeq[char](lines[0].strip.len))

for i, line in lines:
    for j, ch in line.strip:
        grid[i][j] = ch

#echo &"Rows: {grid.len}"
#echo &"Cols: {grid[0].len}"

for i, row in grid:
    var isPartNumber = false
    var number = ""

    for j, ch in row:
        if ch.isDigit:
            number &= ch
            if isAdjacentToCond(grid, i, j, (c) => not c.isDigit and c != '.'):
                isPartNumber = true
        else:
            if isPartNumber:
                #echo number.parseInt
                result += number.parseInt
            #elif number.len > 0:
            #    echo &"Not a part number: {number.parseInt} (row {i}, col {j})"

            number = ""
            isPartNumber = false

    # account for numbers going until the end of the row
    if isPartNumber:
        result += number.parseInt

echo &"Result: {result}"

case fn:
    of "input_03.txt":
        assert result == 559667
    of "sample_input_03.txt":
        assert result == 4361