vault backup: 2025-09-10 10:23:05

Books/代码随想录/代码模版.md

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+# 数组
+## 二分
+```python
+def binary_search(nums, target):
+    left, right = 0, len(nums) - 1
+    while left <= right:
+        mid = left + (right - left) // 2  # 防止溢出
+        if nums[mid] == target:
+            return mid  # 找到目标，返回索引
+        elif nums[mid] < target:
+            left = mid + 1  # 目标在右半部分
+        else:
+            right = mid - 1  # 目标在左半部分
+    return -1  # 未找到目标
+
+# 左右边界
+def left_bound(nums, target):
+    left, right = 0, len(nums) - 1
+    while left <= right:
+        mid = left + (right - left) // 2
+        if nums[mid] < target:
+            left = mid + 1
+        else:
+            right = mid - 1
+    return left if left < len(nums) and nums[left] == target else -1
+def right_bound(nums, target):
+    left, right = 0, len(nums) - 1
+    while left <= right:
+        mid = left + (right - left) // 2
+        if nums[mid] <= target:
+            left = mid + 1
+        else:
+            right = mid - 1
+    return right if right >= 0 and nums[right] == target else -1
+
+```