Add recuresive algorithm code

jbee37142 · jbee37142 · commit d838f35273e4 · 2017-05-28T21:44:23.000+09:00
diff --git a/src/test/java/algorithm/recursion/BraceCombination.java b/src/test/java/algorithm/recursion/BraceCombination.java
@@ -2,6 +2,9 @@
 
 import org.junit.Test;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
 
@@ -14,10 +17,30 @@ public class BraceCombination {
 
     @Test
     public void test() {
-        assertThat("", is(testFunction()));
+        assertThat(null, is(괄호경우의수구하기(0)));
+        List<String> actual = new ArrayList<>();
+        actual.add("(())");
+        actual.add("()()");
+        assertThat(actual, is(괄호경우의수구하기(2)));
+    }
+
+    public List<String> 괄호경우의수구하기(int n) {
+        if (n == 0) {
+            return null;
+        }
+        return combination(n, n, "", new ArrayList<>());
     }
 
-    public String testFunction() {
-        return "";
+    private List<String> combination(int start, int end,
+                                     String pairs, List<String> result) {
+        if (start > end) return result;
+        if (start < 0 || end < 0) return result;
+        if (start == 0 && end == 0) {
+            result.add(pairs);
+            return result;
+        }
+        combination(start - 1, end, pairs + "(", result);
+        combination(start, end - 1, pairs + ")", result);
+        return result;
     }
 }
diff --git a/src/test/java/algorithm/recursion/Dice.java b/src/test/java/algorithm/recursion/Dice.java
@@ -17,6 +17,9 @@ public void test() {
         assertThat(4, is(calcDiceCase(3)));
         assertThat(8, is(calcDiceCase(4)));
         assertThat(16, is(calcDiceCase(5)));
+        assertThat(32, is(calcDiceCase(6)));
+        assertThat(63, is(calcDiceCase(7)));
+        assertThat(125, is(calcDiceCase(8)));
     }
 
     public int calcDiceCase(int n) {

Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,9 @@ public void test() {`
`17`	`17`	`assertThat(4, is(calcDiceCase(3)));`
`18`	`18`	`assertThat(8, is(calcDiceCase(4)));`
`19`	`19`	`assertThat(16, is(calcDiceCase(5)));`
	`20`	`+ assertThat(32, is(calcDiceCase(6)));`
	`21`	`+ assertThat(63, is(calcDiceCase(7)));`
	`22`	`+ assertThat(125, is(calcDiceCase(8)));`
`20`	`23`	`}`
`21`	`24`
`22`	`25`	`public int calcDiceCase(int n) {`