批改作业

01-homework-ligang.py

 #!/usr/bin/env python
-#-*- coding:utf-8 -*-
-def check(s1,s2):
-     print(sum(map(lambda ch:s1.count(ch),s2)))
+# -*- coding:utf-8 -*-
+def check(s1, s2):
+    ## 算法题最好自己来实现 使用基本的数据结构 和操作
+    ## si.count 方法每次要遍历一次字符数组如果 s1的长度为n s2的长度为m 那么计算的时间复杂度是 O(m)*O(n) =O(n^2)
+    ## 试着实现下复杂度为O(n)的算法
+    print(sum(map(lambda ch: s1.count(ch), s2)))
+
 
 def isUnique(str):
     l = list(str)
     n = len(l)
     for i in range(n):
-        if str.count(l[i]) !=1:
+        if str.count(l[i]) != 1:
             print("J value is repeat,please reinput J values")
             exit(0)
 
 
-def alphaCount(str,type=1):
+def alphaCount(str, type=1):
     w = 0
     for i in str:
         if i.isalpha():
-            w +=1
+            w += 1
     if w > 50:
-        if type==1:
+        if type == 1:
             a = 'J'
         else:
-            a ='S'
+            a = 'S'
         print("%s alpha gt 50" % a)
         exit(0)
 
 
-def numJwelsInStones(j,s):
-
-    if j.strip() =='' or s.strip() == '':
+def numJwelsInStones(j, s):
+    if j.strip() == '' or s.strip() == '':
         print("J or S values is not empty")
     else:
-        jcount = alphaCount(j,1)
-        scount = alphaCount(s,2)
+        jcount = alphaCount(j, 1)
+        scount = alphaCount(s, 2)
         isUni = isUnique(j)
-        chek = check(j,s)
+        chek = check(j, s)
+
 
-j = input("please input J value" )
+j = input("please input J value")
 S = input("please input S value ")
-numJwelsInStones(j,S)
+numJwelsInStones(j, S)
+
+
+
+
+# O(n)的实现
+def numJewelsInStones(J, S):
+    stores = {}
+    for c in S:
+        if c in stores:
+            stores[c] = stores[c] + 1
+        else:
+            stores[c] = 1
+
+    count = 0
+    for c in J:
+        if c in stores:
+            count += stores[c]
+    print(count)
+
 
+J = "aA"
+S = "aAAbbbb"
+numJewelsInStones(J, S)
+J = "z"
+S = "ZZ"
+numJewelsInStones(J, S)

02-homework-ligang/mountain.py

@@ -2,6 +2,8 @@
 # -*-coding:utf-8 -*-
 import re
 
+
+# 问题同宝石 时间负责度较高
 def peakIndexInMountainArray(s):
     sp = s.split(',')
     numbers = list(map(int, sp))
@@ -9,9 +11,36 @@ def peakIndexInMountainArray(s):
         print('长度有误 ，重新输入 ')
         exit(0)
     print(numbers.index(max(numbers)))
+
+
 # 格式 为：1,2,3
 st = input("请输入数字，以半角逗号分隔 ,数字不能少于3个或大于10000个 ")
-if not re.search('^[0-9,]+$',st):
-       print ('match error,repeat reinput ')
+if not re.search('^[0-9,]+$', st):
+    print('match error,repeat reinput ')
     exit(0)
 peakIndexInMountainArray(st)
+
+
+# 二分查找 时间复杂度logn的版本
+def peakIndexInMountainArray(mountain):
+    height = len(mountain)
+    low = 0
+    while low <= height:
+        mid = (height + low) // 2
+        if array[mid] > array[mid - 1] and array[mid] > array[mid + 1]:
+            print(mid)
+            break
+        elif array[mid] > array[mid + 1]:
+            height = mid - 1
+        else:
+            low = mid + 1
+
+
+array = [0, 1, 0]
+peakIndexInMountainArray(array)
+array = [0, 2, 1, 0]
+peakIndexInMountainArray(array)
+array = [0, 1, 2, 3, 7, 6, 5, 4, 2, 1, 0]
+peakIndexInMountainArray(array)
+array = [0, 1, 2, 7, 6, 5, 4, 0]
+peakIndexInMountainArray(array)

02-homework-ligang/question_answer.py

@@ -43,3 +43,5 @@ while True:
     else:
         print("我没看懂你的问题")
         break
+
+# 建议使用正则表达式匹配
\ No newline at end of file