poj2250

dp，最长公共子序列变形

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#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;

}