poj2127 Greatest Common Increasing Subsequence

Greatest Common Increasing Subsequence

Time Limit: 10000MS		Memory Limit: 65536K
Total Submissions: 10113		Accepted: 2663
Case Time Limit: 2000MS		Special Judge

Description

You are given two sequences of integer numbers. Write a program to determine their common increasing subsequence of maximal possible length. 
Sequence S₁ , S₂ , . . . , S_N of length N is called an increasing subsequence of a sequence A₁ , A₂ , . . . , A_M of length M if there exist 1 <= i₁ < i₂ < . . . < i_N <= M such that S_j = A_ij for all 1 <= j <= N , and S_j < S_j+1 for all 1 <= j < N .

Input

Each sequence is described with M --- its length (1 <= M <= 500) and M integer numbers A_i (-2³¹ <= A_i < 2³¹ ) --- the sequence itself.

Output

On the first line of the output file print L --- the length of the greatest common increasing subsequence of both sequences. On the second line print the subsequence itself. If there are several possible answers, output any of them.

Sample Input

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

Sample Output

2
1 4

Source

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
int f[1010][1010], a[1010], b[1010], n, m, last, id[1010][1010], ly;
void print(int i, int j, int pos, int& first)
{
    if (j == 0)return ;
    print(i-1,id[i][j], j, first);
    if (j != pos)
    {
        if (first)
        {
            printf("%d", b[j]);
            first = 0;
        }
        else printf(" %d", b[j]);
    }
}
int main()
{
while (~scanf("%d", &n))
{
    for (int i = 1; i <= n; i++)
        scanf("%d", &a[i]);
    scanf("%d", &m);
    for (int i = 1; i <= m; i++)
        scanf("%d", &b[i]);
    memset(f, 0, sizeof(f));
    for (int i = 1; i <= n; i++)
    {
        int maxx = 0;ly = 0;
        for (int j = 1; j <= m; j++)
        {
            f[i][j] = f[i-1][j];
            id[i][j] = j;
            if (a[i] > b[j]&&maxx < f[i-1][j]){maxx = f[i-1][j];ly = j;}
            if (a[i] == b[j]){
                f[i][j] = maxx + 1;
                id[i][j] = ly;
            }
        }
    }
    int maxx = 0;
    for (int i = 1; i <= m; i++)
        if (maxx < f[n][i]){
            maxx = f[n][i];
            last = i;
        }
    printf("%d
", maxx);
    int first = 1;
    print(n, last, 0, first);
    printf("
");
}
}