From 6e357de888c61b269840fb290f01c059330ba1c8 Mon Sep 17 00:00:00 2001
From: Trishun <piotr_dec@msn.com>
Date: Sat, 5 Nov 2022 22:31:46 +0100
Subject: [PATCH] Resolves Java Stack task

---
 .../datastructures/stack/Solution.java        | 41 ++++++++++++
 .../datastructures/stack/SolutionTest.java    | 67 +++++++++++++++++++
 2 files changed, 108 insertions(+)
 create mode 100644 src/main/java/eu/ztsh/training/hackerrank/datastructures/stack/Solution.java
 create mode 100644 src/test/java/eu/ztsh/training/hackerrank/datastructures/stack/SolutionTest.java

diff --git a/src/main/java/eu/ztsh/training/hackerrank/datastructures/stack/Solution.java b/src/main/java/eu/ztsh/training/hackerrank/datastructures/stack/Solution.java
new file mode 100644
index 0000000..00c8102
--- /dev/null
+++ b/src/main/java/eu/ztsh/training/hackerrank/datastructures/stack/Solution.java
@@ -0,0 +1,41 @@
+package eu.ztsh.training.hackerrank.datastructures.stack;
+
+import java.util.Map;
+import java.util.Scanner;
+import java.util.Stack;
+
+/**
+ * Java Stack task.
+ * source: https://www.hackerrank.com/challenges/java-stack
+ */
+public class Solution {
+
+    public static void main(String[] args) {
+        var scanner = new Scanner(System.in);
+        while (scanner.hasNext()) {
+            var stack = new Stack<Character>();
+            var line = scanner.next();
+            for (char input : line.toCharArray()) {
+                if (stack.empty()) {
+                    stack.push(input);
+                    continue;
+                }
+                char head = stack.peek();
+                if (closingChars.getOrDefault(input, '0').equals(head)) {
+                    stack.pop();
+                } else {
+                    stack.push(input);
+                }
+            }
+            System.out.println(stack.empty());
+        }
+
+    }
+
+    private static final Map<Character, Character> closingChars = Map.of(
+            ']', '[',
+            '}', '{',
+            ')', '('
+    );
+
+}
diff --git a/src/test/java/eu/ztsh/training/hackerrank/datastructures/stack/SolutionTest.java b/src/test/java/eu/ztsh/training/hackerrank/datastructures/stack/SolutionTest.java
new file mode 100644
index 0000000..0ecec40
--- /dev/null
+++ b/src/test/java/eu/ztsh/training/hackerrank/datastructures/stack/SolutionTest.java
@@ -0,0 +1,67 @@
+package eu.ztsh.training.hackerrank.datastructures.stack;
+
+import java.util.List;
+import eu.ztsh.training.hackerrank.HackerRankTest;
+import eu.ztsh.training.hackerrank.SolutionClassDescription;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+@DisplayName("HackerRank challenges: Java Stack")
+class SolutionTest extends HackerRankTest {
+
+    @Test
+    public void testCase0() {
+        simpleAssert(
+                List.of(
+                        "{}()",
+                        "({()})",
+                        "{}(",
+                        "[]"
+                ),
+                List.of(
+                        "true",
+                        "true",
+                        "false",
+                        "true"
+                )
+        );
+    }
+
+    @Test
+    public void testCase1() {
+        simpleAssert(
+                List.of(
+                        "({}[])",
+                        "(({()})))",
+                        "({(){}()})()({(){}()})(){()}",
+                        "{}()))(()()({}}{}",
+                        "}}}}",
+                        "))))",
+                        "{{{",
+                        "(((",
+                        "[]{}(){()}((())){{{}}}{()()}{{}{}}",
+                        "[[]][][]",
+                        "}{"
+                ),
+                List.of(
+                        "true",
+                        "false",
+                        "true",
+                        "false",
+                        "false",
+                        "false",
+                        "false",
+                        "false",
+                        "true",
+                        "true",
+                        "false"
+                )
+        );
+    }
+
+    @Override
+    protected SolutionClassDescription getSolutionClassDescription() {
+        return new SolutionClassDescription(Solution.class);
+    }
+
+}