Implement day 4 in Terraform

2024/bonus/day04/check_point/check_x_mas/main.tf

@@ -0,0 +1,30 @@
+variable "grid" {
+  type = list(string)
+}
+
+variable "x" {
+  type = number
+}
+
+variable "y" {
+  type = number
+}
+
+locals {
+  found_a = substr(var.grid[var.y], var.x, 1) == "A"
+
+  c1 = substr(var.grid[var.y - 1], var.x - 1, 1)
+  c2 = substr(var.grid[var.y - 1], var.x + 1, 1)
+  c3 = substr(var.grid[var.y + 1], var.x + 1, 1)
+  c4 = substr(var.grid[var.y + 1], var.x - 1, 1)
+
+  d1 = "${local.c1}${local.c3}"
+  d2 = "${local.c2}${local.c4}"
+
+  found_d1 = contains(["SM", "MS"], local.d1)
+  found_d2 = contains(["SM", "MS"], local.d2)
+}
+
+output "found" {
+  value = local.found_a && local.found_d1 && local.found_d2
+}