binary search re

src/main/java/binarysearch/LeetCode_0034_FindFirstAndLastPositionOfElementInSortedArray.java

@@ -7,46 +7,49 @@ package binarysearch;
 // https://www.cnblogs.com/greyzeng/p/16622554.html
 // https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/description/
 public class LeetCode_0034_FindFirstAndLastPositionOfElementInSortedArray {
-    public int[] searchRange(int[] nums, int target) {
-        if (nums == null || nums.length == 0) {
-            return new int[]{-1, -1};
-        }
-        return new int[]{left(nums, target), right(nums, target)};
-    }
+	public int[] searchRange(int[] nums, int target) {
+		return new int[] { left(nums, target), right(nums, target) };
+	}
 
-    private int left(int[] nums, int target) {
-        int l = 0;
-        int r = nums.length - 1;
-        int ans = -1;
-        while (l <= r) {
-            int m = l + ((r - l) >> 1);
-            if (nums[m] > target) {
-                r = m - 1;
-            } else if (nums[m] < target) {
-                l = m + 1;
-            } else {
-                ans = m;
-                r = m - 1;
-            }
-        }
-        return ans;
-    }
+	private int left(int[] nums, int target) {
+		if (nums == null || nums.length < 1) {
+			return -1;
+		}
+		int l = 0;
+		int r = nums.length - 1;
+		int ans = -1;
+		while (l <= r) {
+			int m = l + ((r - l) >> 1);
+			if (nums[m] == target) {
+				ans = m;
+				r = m - 1;
+			} else if (nums[m] > target) {
+				r = m - 1;
+			} else {
+				l = m + 1;
+			}
+		}
+		return ans;
+	}
 
-    private int right(int[] nums, int target) {
-        int l = 0;
-        int r = nums.length - 1;
-        int ans = -1;
-        while (l <= r) {
-            int m = l + ((r - l) >> 1);
-            if (nums[m] > target) {
-                r = m - 1;
-            } else if (nums[m] < target) {
-                l = m + 1;
-            } else {
-                ans = m;
-                l = m + 1;
-            }
-        }
-        return ans;
-    }
+	private int right(int[] nums, int target) {
+		if (nums == null || nums.length < 1) {
+			return -1;
+		}
+		int l = 0;
+		int r = nums.length - 1;
+		int ans = -1;
+		while (l <= r) {
+			int m = l + ((r - l) >> 1);
+			if (nums[m] == target) {
+				ans = m;
+				l = m + 1;
+			} else if (nums[m] < target) {
+				l = m + 1;
+			} else {
+				r = m - 1;
+			}
+		}
+		return ans;
+	}
 }