先来看个实例
#!/usr/bin/env python import sys def search2(a,m): low = 0 high = len(a) - 1 while(low <= high): mid = (low + high)/2 midval = a[mid] if midval < m: low = mid + 1 elif midval > m: high = mid - 1 else: print mid return mid print -1 return -1 if __name__ == "__main__": a = [int(i) for i in list(sys.argv[1])] m = int(sys.argv[2]) search2(a,m)
运行:
administrator@ubuntu:~/Python$ python test_search2.py 123456789 4
3
注:
1.'__':由于python的类成员都是公有、公开的被存取public,缺少像正统面向对象语言的私有private属性。
于是就用__来将就一下,模拟私有属性。这些__属性往往是内部使用,通常情况下不用改写。也不用读取。
加上2个下划线的目的,一是不和普通公有属性重名冲突,二是不让对象的使用者(非开发者)随意使用。
2.__name__ == "__main__"表示程序脚本是直接被执行的.
如果不等于表示脚本是被其他程序用import引入的.则其__name__属性被设为模块名
Python采用二分查找找出数字的下标
要考虑有重复数字的情况
class Solution(object): def searchRange(self, nums, target): """ :type nums: List[int] :type target: int :rtype: List[int] """ def binary_search(start,end,value): while end>=start: mid = (start+end)//2 print(mid) if nums[mid]>target: end = mid-1 elif nums[mid]<target: start = mid+1 else: if value==-1: if mid-1>=start and nums[mid+value] == target: end = mid+value else: return mid else: if mid+1<=end and nums[mid+value] == target: start = mid+value else: return mid return -1 a=binary_search(0,len(nums)-1,-1) b=binary_search(0,len(nums)-1,1) return [a,b] a = Solution() l = [2,2] print(a.searchRange(l,2))
二分算法的定义不在多说了,百度一下就知道(支持国产大笑)
import sys source = [1,2,3,4,5,6,7,8,9,10] #must be in order des = int(sys.argv[1]) low = 0 high = len(source) - 1 targetIndex = -1 print "des=",des while low <= high: middle = (low + high)/2 if des == source[middle]: targetIndex = middle break elif des < source[middle]: high = middle -1 print "middle element[index=",middle,",value=",source[middle],"] is bigger than des, continue search from[",low,"to",high,"]" else: low = middle + 1 print "middle element[index=",middle,",value=",source[middle],"] is smaller than des, continue search from[",low,"to",high,"]" print "search complete, target element's index in source list is ",targetIndex
最后在分享一个
'fileName--BinarySearch.py' src = [] def BinarySearch(low, high, target, *src): '二分查找' while low <= high: mid = (low + high) // 2 midVal = src[mid] if target < midVal: high = mid - 1 elif target > midVal: low = mid + 1 else: return mid BinarySearch(low, high, target, *src) print('Please input 10 number:') for number in range(10): src.append(int(input('Num %d:' % number))) sortList = tuple(src) key = int(input('Please input key:')) location = BinarySearch(0, len(src) - 1, key, *sortList) if location != None: print('Find target at %d' % (location + 1)) else: print('No target!')
广告合作:本站广告合作请联系QQ:858582 申请时备注:广告合作(否则不回)
免责声明:本站资源来自互联网收集,仅供用于学习和交流,请遵循相关法律法规,本站一切资源不代表本站立场,如有侵权、后门、不妥请联系本站删除!
免责声明:本站资源来自互联网收集,仅供用于学习和交流,请遵循相关法律法规,本站一切资源不代表本站立场,如有侵权、后门、不妥请联系本站删除!
暂无评论...
更新日志
2024年11月25日
2024年11月25日
- 凤飞飞《我们的主题曲》飞跃制作[正版原抓WAV+CUE]
- 刘嘉亮《亮情歌2》[WAV+CUE][1G]
- 红馆40·谭咏麟《歌者恋歌浓情30年演唱会》3CD[低速原抓WAV+CUE][1.8G]
- 刘纬武《睡眠宝宝竖琴童谣 吉卜力工作室 白噪音安抚》[320K/MP3][193.25MB]
- 【轻音乐】曼托凡尼乐团《精选辑》2CD.1998[FLAC+CUE整轨]
- 邝美云《心中有爱》1989年香港DMIJP版1MTO东芝首版[WAV+CUE]
- 群星《情叹-发烧女声DSD》天籁女声发烧碟[WAV+CUE]
- 刘纬武《睡眠宝宝竖琴童谣 吉卜力工作室 白噪音安抚》[FLAC/分轨][748.03MB]
- 理想混蛋《Origin Sessions》[320K/MP3][37.47MB]
- 公馆青少年《我其实一点都不酷》[320K/MP3][78.78MB]
- 群星《情叹-发烧男声DSD》最值得珍藏的完美男声[WAV+CUE]
- 群星《国韵飘香·贵妃醉酒HQCD黑胶王》2CD[WAV]
- 卫兰《DAUGHTER》【低速原抓WAV+CUE】
- 公馆青少年《我其实一点都不酷》[FLAC/分轨][398.22MB]
- ZWEI《迟暮的花 (Explicit)》[320K/MP3][57.16MB]