Add deterministic Java compile smoke test and PR CI check

.github/workflows/compile-smoke.yml

@@ -0,0 +1,22 @@
+name: Java Compile Smoke Test
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  compile-smoke:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '17'
+
+      - name: Run compile smoke test
+        run: ./scripts/compile_smoke.sh

README.md

@@ -78,5 +78,10 @@ These programs are written to clearly show algorithm flow and logic rather than
 ## Development Checks
 - Run a Java compile smoke test:
   ```bash
-  ./scripts/java-compile-smoke.sh
+  ./scripts/compile_smoke.sh
   ```
+- The smoke test:
+  - Scans `Searching-algorithms/`, `Sorting-algorithms/`, and `Data-Structures/`.
+  - Compiles files in deterministic (sorted) order.
+  - Uses isolated temporary output folders per file to avoid default-package collisions.
+  - Prints `[PASS]` / `[FAIL]` per file and exits non-zero when any file fails.

scripts/compile_smoke.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$repo_root"
+
+search_roots=(
+  "Searching-algorithms"
+  "Sorting-algorithms"
+  "Data-Structures"
+)
+
+mapfile -t java_files < <(
+  find "${search_roots[@]}" -type f -name '*.java' 2>/dev/null | LC_ALL=C sort
+)
+
+if [[ ${#java_files[@]} -eq 0 ]]; then
+  echo "No Java files found in target directories: ${search_roots[*]}"
+  exit 0
+fi
+
+tmp_dir="$(mktemp -d)"
+trap 'rm -rf "$tmp_dir"' EXIT
+
+failures=0
+
+echo "Compiling ${#java_files[@]} Java file(s) with isolated output folders..."
+
+for i in "${!java_files[@]}"; do
+  file="${java_files[$i]}"
+
+  work_dir="$tmp_dir/work/$i"
+  out_dir="$tmp_dir/out/$i"
+  err_file="$tmp_dir/err/$i.log"
+  mkdir -p "$work_dir" "$out_dir" "$(dirname "$err_file")"
+
+  class_name="$(sed -nE 's/^[[:space:]]*public[[:space:]]+(class|interface|enum)[[:space:]]+([A-Za-z_][A-Za-z0-9_]*).*/\2/p' "$file" | head -n 1)"
+
+  if [[ -n "$class_name" ]]; then
+    compile_target="$work_dir/${class_name}.java"
+  else
+    compile_target="$work_dir/$(basename "$file")"
+  fi
+
+  cp "$file" "$compile_target"
+
+  if javac -d "$out_dir" "$compile_target" > /dev/null 2>"$err_file"; then
+    echo "[PASS] $file"
+  else
+    echo "[FAIL] $file"
+    sed 's/^/  /' "$err_file"
+    failures=$((failures + 1))
+  fi
+done
+
+if [[ $failures -gt 0 ]]; then
+  echo
+  echo "Java compile smoke test failed: $failures file(s) did not compile."
+  exit 1
+fi
+
+echo
+echo "Java compile smoke test passed."