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Add Java and C++ code for the chapter of

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divide and conquer.
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krahets
2023-07-17 04:20:12 +08:00
parent fc7bcb615d
commit 1f784dadb0
10 changed files with 331 additions and 6 deletions
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11
codes/python/chapter_divide_and_conquer/binary_search_recur.py
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@ -1,22 +1,22 @@
"""
File: binary_search_recur.py
Created Time: 2023-07-17
Author: krahets (xisunyy@163.com)
Author: krahets (krahets@163.com)
"""
def dfs(nums: list[int], target: int, i: int, j: int) -> int:
"""二分查找：分治"""
# 若区间为空，代表未找到目标元素，则返回 -1
"""二分查找：问题 f(i, j)"""
# 若区间为空，代表无目标元素，则返回 -1
if i > j:
return -1
# 计算中点索引 m
m = (i + j) // 2
if nums[m] < target:
# 此情况说明 target 在区间 [m+1, j] 中，递归解决该子问题
# 递归子问题 f(m+1, j)
return dfs(nums, target, m + 1, j)
elif nums[m] > target:
# 此情况说明 target 在区间 [i, m-1] 中，递归解决该子问题
# 递归子问题 f(i, m-1)
return dfs(nums, target, i, m - 1)
else:
# 找到目标元素，返回其索引
@ -26,6 +26,7 @@ def dfs(nums: list[int], target: int, i: int, j: int) -> int:
def binary_search(nums: list[int], target: int) -> int:
"""二分查找"""
n = len(nums)
# 求解问题 f(0, n-1)
return dfs(nums, target, 0, n - 1)