Add selection sort code

jbee37142 · jbee37142 · commit 6f9b7d22d6ed · 2017-06-04T16:36:51.000+09:00
diff --git a/src/test/java/sort/SelectionSort.java b/src/test/java/sort/SelectionSort.java
@@ -0,0 +1,54 @@
+package sort;
+
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+public class SelectionSort {
+
+    /*
+        TASK
+     */
+
+    @Test
+    public void test() {
+        int[] arr1 = {};
+        int[] sortedArr1 = {};
+        assertThat(solution(arr1), is(sortedArr1));
+        int[] arr2 = {6,4,1,8,9,2,7,5,3};
+        int[] sortedArr2 = {1,2,3,4,5,6,7,8,9};
+        assertThat(solution(arr2), is(sortedArr2));
+        int[] arr3 = {1};
+        int[] sortedArr3 = {1};
+        assertThat(solution(arr3), is(sortedArr3));
+
+        int[] arr = {1,2,3};
+        int[] chagedArr = {1,3,2};
+        assertThat(swapValue(arr, 1,2), is(chagedArr));
+    }
+
+    public int[] solution(int[] arr) {
+        if (arr == null) return null;
+        int[] result = arr;
+        int maxPos;
+
+        for (int i = 0; i < result.length - 1; i++) {
+            maxPos = i;
+            for (int k = i + 1g; k < result.length; k++) {
+                if (result[maxPos] > result[k]) {
+                    maxPos = k;
+                }
+            }
+            result = swapValue(result, i, maxPos);
+        }
+        return result;
+    }
+
+    private int[] swapValue(int[] arr, int a, int b) {
+        int temp = arr[a];
+        arr[a] = arr[b];
+        arr[b] = temp;
+        return arr;
+    }
+}
