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
+    if num_list[mid] == 9:
+        print("9的索引为",mid)
+        break
+    if num_list[mid] < 9:
+        low = mid +1
+    if num_list[mid] > 9:
+        high = mid -1
+    if high < low:
+        print("没有")
+        break
+
+low = 0
+high = len(num_list) -1
+while True:
+    mid = (low +high) //2
+    if num_list[mid] == 20:
+        print("20的索引为",mid)
+        break
+    if num_list[mid] < 20:
+        low = mid +1
+    if num_list[mid] > 20:
+        high = mid -1
+    if high < low:
+        print("没有")
+        break
+
+# [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
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