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]
+high=9
+low=0
+while True:
+    mid=(high+low)//2
+    if low<=high:
+        if num_list[mid]==9:
+            print("9在列表里的索引为"+str(mid))
+            break
+        elif num_list[mid]<9:
+            low=mid+1
+        elif num_list[mid]>9:
+            high=mid-1
+        
+    if low>high:
+        print("找不到9在列表里的索引")
+        break
+high=9
+low=0
+while True:
+    mid=(high+low)//2
+    if low<=high:
+        if num_list[mid]==20:
+            print("20在列表里的索引为"+str(mid))
+            break
+        elif num_list[mid]<20:
+            low=mid+1
+        elif num_list[mid]>20:
+            high=mid-1
+        
+    if low>high:
+        print("找不到20在列表里的索引")
+        break
+        
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