Refine the solution for LC #33

rayworks · Dec 20, 2023 · 930dfa8 · 930dfa8
1 parent b3878d5
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diff --git a/src/main/java/org/sean/array/ArraySearch.java b/src/main/java/org/sean/array/ArraySearch.java
@@ -4,6 +4,43 @@
  * 33. Search in Rotated Sorted Array
  */
 public class ArraySearch {
+    public int searchExt(int[] nums, int target) {
+        if (nums == null || nums.length == 0) {
+            return -1;
+        }
+        int left = 0;
+        int right = nums.length - 1;
+        while (left <= right) {
+            // check two ends
+            if (nums[left] == target) return left;
+            if (nums[right] == target) return right;
+
+            // eg:
+            //4567012
+            //5670124
+            int mid = left + (right - left) / 2;
+            if (nums[mid] == target) {
+                return mid;
+            } else if (nums[mid] > nums[left]) { // if it's already sorted in the left half
+                if (nums[mid] > target && nums[left] < target) { // check the target position in sorted range
+                    right = mid - 1;
+                    left++;
+                } else {
+                    left = mid + 1;
+                }
+            } else {
+                // else right half is sorted
+                if (nums[mid] < target && nums[right] > target) {
+                    left = mid + 1;
+                    right--;
+                } else {
+                    right = mid - 1;
+                }
+            }
+        }
+        return -1;
+    }
+
     // region Time O(logN)
     private int doBinSearch(int[] nums, int l, int r, int target) {
         while (l <= r) {

diff --git a/src/test/java/org/sean/array/ArraySearchTest.java b/src/test/java/org/sean/array/ArraySearchTest.java
@@ -18,4 +18,12 @@ public void setUp() throws Exception {
     public void search() {
         assertEquals(-1, finder.search(new int[]{4, 5, 6, 7, 0, 1, 2}, 3));
     }
+
+    @Test
+    public void testSearch() {
+        assertEquals(-1, finder.searchExt(new int[]{4, 5, 6, 7, 0, 1, 2}, 3));
+        assertEquals(4, finder.searchExt(new int[]{4, 5, 6, 7, 0, 1, 2}, 0));
+        assertEquals(0, finder.searchExt(new int[]{4, 5, 6, 7, 0, 1, 2}, 4));
+        assertEquals(6, finder.searchExt(new int[]{4, 5, 6, 7, 0, 1, 2}, 2));
+    }
 }