Add java solution for 34 (qiyuangong#65)

BHwi · web-flow · commit 354044a9eebe · 2022-10-08T21:59:10.000+08:00
* Add 034_Find_First_and_Last_Position_of_Element_in_Sorted_Array.java Contributed by @BHwi
diff --git a/java/034_Find_First_and_Last_Position_of_Element_in_Sorted_Array.java b/java/034_Find_First_and_Last_Position_of_Element_in_Sorted_Array.java
@@ -0,0 +1,59 @@
+class Solution {
+    /*
+        Rule 1
+        - Given array is sorted in non-decreasing order
+        
+        Rule 2
+        - Limit time complexity O(log n).
+        
+        So I can use Binary Search Algorithm.
+    */
+    public int[] searchRange(int[] nums, int target) {
+        // initialize arr[0] -> maximum integer, arr[1] -> minimum integer
+        int[] arr = {100001, -10};
+        int s = 0;
+        int e = nums.length - 1;
+        
+        // find minimum index in nums with Binary Search alogorithm
+        while (s <= e) {
+            
+            int mid = (s + e) / 2;
+            
+            if(nums[mid] > target) {
+                e = mid - 1;
+            }
+            else if(nums[mid] <= target) {
+                if(nums[mid] == target) {
+                    arr[0] = Math.min(arr[0], mid);
+                    arr[1] = Math.max(arr[1], mid);
+                }
+                s = mid + 1;
+            }
+        }
+        
+        s = 0;
+        e = nums.length - 1;
+        
+        // find maximum index in nums with Binary Search alogorithm
+        while(s <= e) {
+            int mid = (s + e) / 2;
+            
+            if(nums[mid] >= target) {
+                if(nums[mid] == target) {
+                    arr[0] = Math.min(arr[0], mid);
+                    arr[1] = Math.max(arr[1], mid);
+                }
+                e = mid - 1;
+            }
+            else if(nums[mid] < target) {
+                s = mid + 1;
+            }
+        }
+        
+        // if arr data is initial data, set -1.
+        if(arr[0] == 100001) arr[0] = -1;
+        if(arr[1] == -10) arr[1] = -1;
+        
+        return arr;
+    }
+}
