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 =20
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+num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+
+
+def a(w,num):
+    low = 0
+    high =len(w)-1
+    while low<=high:
+        mid = (low+high)//2
+        guess =w[mid]
+        if guess ==num:
+            return num
+        elif guess<num:
+            low =mid+1
+        else:
+            high =mid-1
+
+    return None
+x=a(num_list,num)
+print(x)
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