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 = 0
+high = len(num_list)-1
+
+while True:
+    mid = (low+high)//2
+    guess = num_list[mid]
+    if guess == 20:
+        print('找到这个数了！')
+        print(str(mid))
+        break
+    elif guess < 20:
+        low = mid+1
+    else:
+        high = mid-1
+    if high <= low:
+        print('没有这个数！')
+        break
+low = 0
+high = len(num_list)-1
+while True:
+    mid = (low+high)//2
+    guess = num_list[mid]
+    if guess == 9:
+        print('找到这个数了！')
+        print(str(mid))
+        break
+    elif guess < 9:
+        low = mid+1
+    else:
+        high = mid-1
+    if high <= low:
+        print('没有这个数！')
+        break
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