save project

binary_search.py

 # 使用二分查找法，找出9和20在列表里面的索引
 # 使用二分查找法，找出9和20在列表里面的索引
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+
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+low=0
+mid=0
+num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+high=len(num_list)-1
+while high>=low and num_list[mid]!=9:
+    mid=(high+low)//2
+    if num_list[mid]<9:
+        low=mid+1
+    if num_list[mid]>9:
+        high=mid-1
+if num_list[mid]!=9:
+    print("没有9")
+else:
+    print("9的索引是",mid)
+low=0
+high=len(num_list)-1
+while high>=low and num_list[mid]!=20:
+    mid=(high+low)//2
+    if num_list[mid]<20:
+        low=mid+1
+    if num_list[mid]>20:
+        high=mid-1
+if num_list[mid]!=20:
+    print("没有20")
+else:
+    print("20的索引是",mid)
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