Day 08 part 1

const 
  FOREST_SZ = 99

type
  ForestMap = array[FOREST_SZ, array[FOREST_SZ, char]]

var
  forest: ForestMap
  answer: Natural

proc isEdge(x, y: Natural): bool {.inline.} =
  x == 0 or x == FOREST_SZ-1 or y == 0 or y == FOREST_SZ-1

proc isVisible(x, y: Natural): bool =
  if isEdge(x, y): return true
  for i in countdown(x-1, 0): 
    if forest[i][y] >= forest[x][y]: break
    if isEdge(i, y): return true
  for i in x+1..<FOREST_SZ: 
    if forest[i][y] >= forest[x][y]: break
    if isEdge(i, y): return true
  for i in countdown(y-1, 0): 
    if forest[x][i] >= forest[x][y]: break
    if isEdge(x, i): return true
  for i in y+1..<FOREST_SZ:
    if forest[x][i] >= forest[x][y]: break
    if isEdge(x, i): return true
  
proc readFile() =
  var lIdx: Natural
  for line in "input.txt".lines:
    for col in 0..<line.len:
      forest[lIdx][col] = line[col]  # to avoid str allocation
    lIdx.inc

readFile()

for x in 0..<FOREST_SZ:
  for y in 0..<FOREST_SZ:
    if isVisible(x, y): answer.inc

Answer is: 1851