题目
总时间限制: 2000ms 内存限制: 65536kB
描述
A numeric sequence of ai is ordered if a1 < a2 < … < aN. Let the subsequence of the given numeric sequence (a1, a2, …, aN) be any sequence (ai1, ai2, …, aiK), where 1 <= i1 < i2 < … < iK <= N. For example, sequence (1, 7, 3, 5, 9, 4, 8) has ordered subsequences, e. g., (1, 7), (3, 4, 8) and many others. All longest ordered subsequences are of length 4, e. g., (1, 3, 5, 8).
Your program, when given the numeric sequence, must find the length of its longest ordered subsequence.
输入
The first line of input file contains the length of sequence N. The second line contains the elements of sequence - N integers in the range from 0 to 10000 each, separated by spaces. 1 <= N <= 1000
输出
Output file must contain a single integer - the length of the longest ordered subsequence of the given sequence.
样例输入
7
1 7 3 5 9 4 8
样例输出
4
来源
Northeastern Europe 2002, Far-Eastern Subregion
思路
动态规划。maxlen(k)表示以ak为终点的最长上升子序列长度.
代码
while True:
try:
N = int(input().strip())
nums = input().strip().split()
nums = [int(i) for i in nums]
dp = []
dp.append(1)
for i in range(1, N):
maxnum = 0
for j in range(0, i):
if nums[i] > nums[j] and maxnum < dp[j]:
maxnum = dp[j]
dp.append(maxnum + 1)
print(max(dp))
except:
break