模板 - 最长公共子序列

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最长公共子序列

#include <stdio.h>#include <iostream>#include <string.h>#include <algorithm>using namespace std;string str;char s1[1000], s2[1000];int dp[1000][1000], mark[1000][1000];///数据太大，dp数组变成滚动数组int LCS(){    int i, j, n, m;    memset(dp,0,sizeof(dp));    n = strlen(s1);    m = strlen(s2);    for(i = 0; i <= n; i++)        mark[i][0] = 1;    for(i = 0; i <= m; i++)        mark[0][i] = -1;    for(i = 1; i <= n; i++)    {        for(j = 1; j <= m; j++)        {            if(s1[i-1] == s2[j-1])            {                dp[i][j] = dp[i-1][j-1] + 1;                mark[i][j] = 0;            }            else if(dp[i-1][j] >= dp[i][j-1])            {                dp[i][j] = dp[i-1][j];                mark[i][j] = 1;            }            else            {                dp[i][j] = dp[i][j-1];                mark[i][j] = -1;            }        }    }    return dp[n][m];}void SameLCS(int i,int j)///mark[i][j] == 1表示s1序列的,mark[i][j] == -1表示s2序列的{    if(!i && !j)        return ;    if(mark[i][j] == 0)///公共序列    {        SameLCS(i-1,j-1);        str += s1[i-1];    }    else if(mark[i][j] == 1)        SameLCS(i-1,j);    else        SameLCS(i,j-1);}int main(){    while(~scanf("%s %s",s1,s2))    {        int ans, len1, len2;        len1 = strlen(s1);        len2 = strlen(s2);        ans = LCS();        printf("%d\n",ans);        SameLCS(len1,len2);        cout << str << endl;    }    return 0;}

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