LeetCode——Consecutive Numbers
Description:
Write a SQL query to find all numbers that appear at least three times consecutively.
+----+-----+ | Id | Num | +----+-----+ | 1 | 1 | | 2 | 1 | | 3 | 1 | | 4 | 2 | | 5 | 1 | | 6 | 2 | | 7 | 2 | +----+-----+
For example, given the above Logs
table, 1
is the only number that appears consecutively for at least three times.
要查出连续至少出现3次的Num。需要3个循环套一起,但是时间复杂度是O(n),因为每个循环实际上只遍历了一次。
# Write your MySQL query statement below select DISTINCT(l1.Num) from Logs l1, Logs l2, Logs l3 where l1.Id+1=l2.Id and l1.Id+2=l3.Id and l1.Num=l2.Num and l1.Num=l3.Num;
作者:Pickle
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