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]
 num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-a=17
+a=10
 low=0
 low=0
 high=9
 high=9
 mid=(low+high)//2
 mid=(low+high)//2
 while True:
 while True:
-    if num_list[mid]==a:
-        print(mid)
-        break
-    elif a<num_list[mid]:
-        high=mid-1
+    if low<=high:
+        if num_list[mid]==a:
+            print(mid)
+            break
+        elif a<num_list[mid]:
+            high=mid-1
+        else:
+            low=mid+1
+        mid=(low+high)//2
     else:
     else:
-        low=mid+1
-    mid=(low+high)//2
-    
+        print('结束')
+        break
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