Merged config.json

config.json

@@ -50,6 +50,7 @@
     "minesweeper",
     "series",
     "robot-simulator",
+    "bracket-push",
     "binary-search"
   ],
   "exercises": [
@@ -284,6 +285,11 @@
       "topics": []
     },
     {
+      "slug": "bracket-push",
+      "difficulty": 1,
+      "topics": []
+    },
+    {
       "slug": "binary-search",
       "difficulty": 1,
       "topics": []

exercises/bracket-push/build.gradle

@@ -0,0 +1,17 @@
+apply plugin: "java"
+apply plugin: "eclipse"
+apply plugin: "idea"
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  testCompile "junit:junit:4.12"
+}
+test {
+  testLogging {
+    exceptionFormat = 'full'
+    events = ["passed", "failed", "skipped"]
+  }
+}

exercises/bracket-push/src/example/java/BracketChecker.java

@@ -0,0 +1,45 @@
+import java.util.*;
+
+final class BracketChecker {
+
+    private static final Map<Character, Character> BRACKET_PAIR_MAP = new HashMap<Character, Character>() {{
+        put('[', ']');
+        put('{', '}');
+        put('(', ')');
+    }};
+
+    private static boolean isOpeningBracket(final char character) {
+        return BRACKET_PAIR_MAP.keySet().contains(character);
+    }
+
+    private static boolean isClosingBracket(final char character) {
+        return BRACKET_PAIR_MAP.values().contains(character);
+    }
+
+    private final String expression;
+
+    BracketChecker(final String expression) {
+        this.expression = expression;
+    }
+
+    boolean areBracketsMatchedAndNestedCorrectly() {
+        final Stack<Character> bracketsStack = new Stack<>();
+
+        for (final char character : expression.toCharArray()) {
+            if (isOpeningBracket(character)) {
+                bracketsStack.push(character);
+            } else if (isClosingBracket(character)) {
+                if (bracketsStack.isEmpty()) {
+                    return false;
+                }
+
+                if (!BRACKET_PAIR_MAP.get(bracketsStack.pop()).equals(character)) {
+                    return false;
+                }
+            }
+        }
+
+        return bracketsStack.isEmpty();
+    }
+
+}

exercises/bracket-push/src/main/java/BracketChecker.java

@@ -0,0 +1,5 @@
+final class BracketChecker {
+
+
+
+}

exercises/bracket-push/src/test/java/BracketCheckerTest.java

@@ -0,0 +1,102 @@
+import org.junit.Ignore;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public final class BracketCheckerTest {
+
+    @Test
+    public void testPairedSquareBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("[]");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testEmptyString() {
+        final BracketChecker bracketChecker = new BracketChecker("");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testUnpairedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("[[");
+        assertFalse(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testIncorrectlyOrderedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("}{");
+        assertFalse(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testPairedBracketsWithWhitespace() {
+        final BracketChecker bracketChecker = new BracketChecker("{ }");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testSimpleNestedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("{[]}");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testSeveralPairedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("{}[]");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testPairedAndNestedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("([{}({}[])])");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testUnopenedClosingBracket() {
+        final BracketChecker bracketChecker = new BracketChecker("{[)][]}");
+        assertFalse(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testUnpairedAndNestedBracket() {
+        final BracketChecker bracketChecker = new BracketChecker("([{])");
+        assertFalse(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testPairedAndIncorrectlyNestedBrackets() {
+        final BracketChecker bracketChecker = new BracketChecker("[({]})");
+        assertFalse(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testValidMathExpression() {
+        final BracketChecker bracketChecker = new BracketChecker("(((185 + 223.85) * 15) - 543)/2");
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+    @Ignore
+    @Test
+    public void testValidComplexLaTeXExpression() {
+        final BracketChecker bracketChecker = new BracketChecker(
+                "\\left(\\begin{array}{cc} \\frac{1}{3} & x\\\\ \\mathrm{e}^{x} &... x^2 \\end{array}\\right)");
+
+        assertTrue(bracketChecker.areBracketsMatchedAndNestedCorrectly());
+    }
+
+}

exercises/settings.gradle

@@ -7,6 +7,7 @@ include 'beer-song'
 include 'binary'
 include 'binary-search'
 include 'bob'
+include 'bracket-push'
 include 'crypto-square'
 include 'difference-of-squares'
 include 'etl'