Greatest Common Increasing Subsequence【 HDU - 1423 】

最新推荐文章于 2020-05-04 14:47:55 发布

原创最新推荐文章于 2020-05-04 14:47:55 发布 · 216 阅读

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本文介绍了一种解决最长公共上升子序列问题的算法实现。该问题要求找出两个整数序列中，长度最长的共同上升子序列。通过动态规划的方法，算法能够有效地找到这一子序列的长度。

This is a problem from ZOJ 2432.To make it easyer,you just need output the length of the subsequence.

Input

Each sequence is described with M - its length (1 <= M <= 500) and M integer numbers Ai (-2^31 <= Ai < 2^31) - the sequence itself.

Output

output print L - the length of the greatest common increasing subsequence of both sequences.

Sample Input

1

5
1 4 2 5 -12
4
-12 1 2 4

Sample Output

题意：

这是一道典型的求最长公共子序列问题。

求出两个数组公共的最长的上升子序列（可以不是连续的子序列）。

代码：

#include<stdio.h>
#include<string.h>

int t,l1,l2,k;
int s1[510], s2[510];
int dp[510];

int song()
{
    memset(dp, 0, sizeof(dp));
    for (int i = 1; i <= l1; ++i)
    {
        k = 0;
        for (int j = 1; j <= l2; ++j)
        {
            if (s1[i] > s2[j] && k < dp[j])
                k = dp[j];
                
            if (s1[i] == s2[j])
                dp[j] = k+ 1;
        }
    }
    k = 0;
    for (int i = 1; i <= l2; ++i)
    {
        if (k < dp[i])
            k = dp[i];
    }
    return k;
}

int main()
{
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d", &l1);
        for (int i = 1; i <= l1; ++i)
            scanf("%d", &s1[i]);

        scanf("%d", &l2);
        for (int i = 1; i <= l2; ++i)
            scanf("%d", &s2[i]);

        printf("%d\n", song());
        if (t)
            putchar('\n');
    }
    return 0;
}