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
-bingo_num = 20
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-low = 0
-high = len(num_list)-1
-while low <=high:
+def binary_search(alist,num)
+    low = 0
+    high = len(alist)-1
+    while low <=high:
         mid = (low+high)//2
         mid = (low+high)//2
-    guess_num = num_list[mid]
-    if guess_num == bingo_num:
-        print('找到了：',mid)
-        break
-    elif guess_num < bingo_num:
-        low = mid+1
-    elif guess_num > bingo_num:
-        high = mid-1    
+        guess = alist[mid]
+        if guess == num:
+            return mid
+        elif guess < num:
+            low = mid +1
+        else:
+            high = mid - 1
+    return None
\ No newline at end of file
+
+result= binary_search(alist,num)
+print("數是",num)
+print("索引是",result)
\ No newline at end of file