fix 540

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_540.java

@@ -17,11 +17,11 @@ public int singleNonDuplicate(int[] nums) {
             int end = nums.length - 1;
             while (start < end) {
                 int mid = start + (end - start) / 2;
-                if (nums[mid] != nums[mid + 1] && nums[mid] != nums[mid - 1]) {
+                if (mid + 1 < nums.length && nums[mid] != nums[mid + 1] && mid - 1 >= 0 && nums[mid] != nums[mid - 1]) {
                     return nums[mid];
-                } else if (nums[mid] == nums[mid + 1] && mid % 2 == 0) {
+                } else if (mid + 1 < nums.length && nums[mid] == nums[mid + 1] && mid % 2 == 0) {
                     start = mid + 1;
-                } else if (nums[mid] == nums[mid - 1] && mid % 2 == 1) {
+                } else if (mid - 1 >= 0 && nums[mid] == nums[mid - 1] && mid % 2 == 1) {
                     start = mid + 1;
                 } else {
                     end = mid - 1;

src/test/java/com/fishercoder/_540Test.java

@@ -55,4 +55,13 @@ public void test4() {
         assertEquals(expected, solution2.singleNonDuplicate(nums));
         assertEquals(expected, solution3.singleNonDuplicate(nums));
     }
+
+    @Test
+    public void test5() {
+        nums = new int[]{1, 2, 2, 3, 3};
+        expected = 1;
+        assertEquals(expected, solution1.singleNonDuplicate(nums));
+        assertEquals(expected, solution2.singleNonDuplicate(nums));
+        assertEquals(expected, solution3.singleNonDuplicate(nums));
+    }
 }