使用Python实现递归、非递归方式实现折半查找算法,在26个大写英文字母中查找字符其中的字符串以K为例如。
- 递归实现折半查找算法:
#递归实现折半查找算法:
def binary_search_recursive(arr, low, high, target):
if high >= low:
mid = (high + low) // 2
if arr[mid] == target:
return mid
elif arr[mid] > target:
return binary_search_recursive(arr, low, mid - 1, target)
else:
return binary_search_recursive(arr, mid + 1, high, target)
else:
return -1
letters = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q',
'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
target = 'K'
result = binary_search_recursive(letters, 0, len(letters) - 1, target)
if result != -1:
print(f"{target}在字母表中的索引是{result}")
else:
print(f"{target}不在字母表中")
递归实现折半查找算法运行结果截图
2.非递归实现折半查找算法:
def binary_search_iterative(arr, target):
low = 0
high = len(arr) - 1
while low <= high:
mid = (high + low) // 2
if arr[mid] == target:
return mid
elif arr[mid] > target:
high = mid - 1
else:
low = mid + 1
return -1
letters = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
target = 'K'
result = binary_search_iterative(letters, target)
if result != -1:
print(f"{target}在字母表中的索引是{result}")
else:
print(f"{target}不在字母表中")
非递归实现折半查找算法运行结果截图