2024/11/10 灵茶题单 二分查找

src/main/java/com/cool/ling_cha_mount/binary_search/Num34.java

@@ -0,0 +1,31 @@
+package com.cool.ling_cha_mount.binary_search;
+
+/**
+ * @author : Cool
+ * @date: 2024/11/08
+ * 34. 在排序数组中查找元素的第一个和最后一个位置
+ */
+public class Num34 {
+    public int[] searchRange(int[] nums, int target) {
+        int start = binarySearch(nums, target);
+        if (start < nums.length && nums[start] == target) {
+            int end = binarySearch(nums, target + 1) - 1;
+            return new int[]{start, end};
+        }
+        return new int[]{-1, -1};
+    }
+
+    public int binarySearch(int[] nums, int target) {
+        int left = 0;
+        int right = nums.length - 1;
+        while (left <= right) {
+            int mid = (right - left) / 2 + left;
+            if (nums[mid] < target) {
+                left = mid + 1;
+            } else {
+                right = mid - 1;
+            }
+        }
+        return left;
+    }
+}

src/main/java/com/cool/ling_cha_mount/binary_search/Num704.java

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+package com.cool.ling_cha_mount.binary_search;
+
+/**
+ * @author : Cool
+ * @date: 2024/11/10
+ * 704. 二分查找
+ */
+public class Num704 {
+    public int search(int[] nums, int target) {
+        int left = 0;
+        int right = nums.length - 1;
+        while (left <= right) {
+            int mid = (right - left) / 2 + left;
+            if (nums[mid] > target) {
+                right = mid - 1;
+            } else if (nums[mid] < target) {
+                left = mid + 1;
+            } else {
+                return mid;
+            }
+        }
+        return -1;
+    }
+}