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
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
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+num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+low,high=0,len(num_list)-1
+while True:
+    num=int(input("输入："))
+    if high>=low:
+        while True:
+            mid=(high+low)//2
+            gusses=num_list[mid]
+            if gusses==num:
+                print("索引为",mid)
+                break
+            elif gusses<num:
+                low=mid+1
+                if high<low:
+                    print("此数不存在")
+                    break
+            else:
+                high=mid-1
+                if high<low:
+                    print("此数不存在")
+                    break
\ No newline at end of file