Day17 2021 in nim

2021/nim/17/example.txt

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+target area: x=20..30, y=-10..-5

2021/nim/17/input.txt

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+target area: x=139..187, y=-148..-89

2021/nim/17/main.nim

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+import nre, strutils
+
+let
+    regex = re"x=(-?\d+)..(-?\d+), y=(-?\d+)..(-?\d+)"
+    data = readFile("input.txt")
+    captures = data.find(regex).get.captures
+    x1 = captures[0].parseInt()
+    x2 = captures[1].parseInt()
+    y1 = captures[2].parseInt()
+    y2 = captures[3].parseInt()
+    minX = min(x1, x2)
+    maxX = max(x1, x2)
+    minY = min(y1, y2)
+    maxY = max(y1, y2)
+
+proc land(dx: int, dy: int): int =
+    var dx = dx
+    var dy = dy
+    var x = 0
+    var y = 0
+    var high = y
+    while x < maxX and y > minY:
+        x += dx
+        y += dy
+        if dx > 0: dx -= 1
+        elif dx < 0: dx += 1
+        dy -= 1
+        high = max(high, y)
+        if x in minX..maxX and y in minY..maxY:
+            return high
+    return -1
+
+var high = 0
+var match = 0
+for x in -1000..1000:
+    for y in -1000..1000:
+        let res = land(x, y)
+        if res != -1: match += 1
+        high = max(res, high)
+
+echo(high)
+echo(match)