poj2250

dp，最长公共子序列变形

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

const int maxn = 105, maxl = 45;

int text1[maxn], text2[maxn], len1, len2;
char dic[maxn * 2][maxl];
int tot;
char first[maxl];
int f[maxn][maxn], from[maxn][maxn];
int stk[maxn];

int getid(char *word)
{
    for (int i = 0; i < tot; i++)
        if (strcmp(dic[i], word) == 0)
            return i;
    strcpy(dic[tot++], word);
    return tot - 1;
}

void input(int text[], int &len)
{
    char word[maxl];
    int i = 1;

    strcpy(word, first);
    while (strcmp(word, "#"))
    {
        text[i++] = getid(word);
//        printf("%d %d\n", i - 1, text[i - 1]);
        scanf("%s", word);
    }
    len = i - 1;
}

void work()
{
    for (int i = 1; i <= len1; i++)
    {
        for (int j = 1; j <= len2; j++)
        {
            if (f[i - 1][j] > f[i][j - 1])
            {
                from[i][j] = 0;
                f[i][j] = f[i - 1][j];
            }
            else
            {
                from[i][j] = 1;
                f[i][j] = f[i][j - 1];
            }
            if (text1[i] == text2[j] && f[i][j] < f[i - 1][j - 1] + 1)
            {
                f[i][j] = f[i - 1][j - 1] + 1;
                from[i][j] = 2;
            }
//            printf("%d %d %d\n", i, j, f[i][j]);
        }
    }

    int a = len1, b = len2;
    int rear = 0;
    while (a && b)
    {
        if (from[a][b] == 0)
            a--;
        else if (from[a][b] == 1)
            b--;
        else
        {
            stk[rear++] = text1[a];
            a--;
            b--;
        }
    }

//    printf("%d %d %d\n", rear, len1, len2);
    printf("%s", dic[stk[rear - 1]]);
    for (int i = rear - 2; i >= 0; i--)
        printf(" %s", dic[stk[i]]);
    printf("\n");
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (~scanf("%s", first))
    {
        memset(f, 0, sizeof(f));
        tot = 0;
        input(text1, len1);
        scanf("%s", first);
        input(text2, len2);
        work();
    }
    return 0;
}