poj 2127 Greatest Common Increasing Subsequence (记录路径LICS)

题意：求最长递增公共子序列

这道题需要将该序列输出，这就牵涉到了路径记录的问题.

</pre><pre class="sio" name="code" style="white-space: pre-wrap; word-wrap: break-word; font-size: 14px; line-height: 26px; background-color: rgb(255, 255, 255);"><pre name="code" class="cpp">#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;

int a[505],b[505],dp[505],n,m,cnt;
int mark[505][505],ans[505];

int LICS()
{
    int i,j,MAX,k;
    memset(dp,0,sizeof(dp));
    memset(mark,0,sizeof(mark));
    for(i = 1; i<=n; i++)
    {
        memcpy(mark[i],mark[i-1],sizeof(mark[0]));
        k = 0;
        for(j = 1; j<=m; j++)
        {
            if(a[i-1]>b[j-1] && dp[k]<dp[j])
                k = j;
            if(a[i-1]==b[j-1] && dp[k]+1>dp[j])
            {
                dp[j] = dp[k]+1;
                mark[i][j] = i*(m+1)+k;;
            }
        }
    }
    MAX = 0;
    for(i = 1; i<=m; i++)
        if(dp[MAX]<dp[i])
            MAX = i;
    i = m*n+n+MAX;
    for(j = dp[MAX];j>0;j--)
    {
        ans[j-1] = b[i%(m+1)-1];
        i = mark[i/(m+1)][i%(m+1)];
    }
    return dp[MAX];
}

int main()
{
    int i,k;
    while(~scanf("%d",&n))
    {
        for(i = 0; i<n; i++)
            scanf("%d",&a[i]);
        scanf("%d",&m);
        for(i = 0; i<m; i++)
            scanf("%d",&b[i]);
        cnt = 0;
        k = LICS();
        printf("%d
",k);
        for(i = 0;i<k;i++)
        {
            if(i)
            printf(" ");
            printf("%d",ans[i]);
        }
        printf("
");
    }

    return 0;
}

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