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diy2.py

@@ -4,4 +4,31 @@ for i in range(0,len(alist)-1):
         if alist[j]>alist[j+1]:
         if alist[j]>alist[j+1]:
             alist[j],alist[j+1] = alist[j+1],alist[j]
             alist[j],alist[j+1] = alist[j+1],alist[j]
 print(alist)
 print(alist)
-    
+import random
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+alist = []
+for i in range(1, 101):
+    alist.append(i)
+num = random.choice(alist)
+for i in range(0,len(alist)-1):
+    for j in range(0,len(alist)-1):
+        if alist[j]>alist[j+1]:
+            alist[j],alist[j+1] = alist[j+1],alist[j]
+# 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
+for i in range(len(alist)-1):
+    if i 
+def binary_search(alist,num):
+    low = 0
+    high = len(alist) - 1
+    while low < high:
+        mid = (low + high)//2
+        guess = alist[mid]
+        if guess == num:
+            print("找到了")
+            print(str(num)+"的索引为"+str(mid))
+            break
+        elif guess < num:
+            low = mid + 1
+        else:
+            high = mid -1
+    return num
+binary_search(alist,num)
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