Aizu2090LCS

Posted 2021-08-29 hesorchen

题目

Problem G: Repeated Subsequences

暴力分割，之后求LCS即可。

代码

#include <bits/stdc++.h>
using namespace std;

int dp[1010][1010];

string get(string a, string b)
{
    // memset(dp, 0, sizeof dp);

    int n = a.size(), m = b.size();
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            dp[i][j] = 0;
    a = '#' + a;
    b = '#' + b;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            if (a[i] == b[j])
                dp[i][j] = max(dp[i - 1][j - 1] + 1, dp[i][j]);
            else
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
        }
    int p1 = n, p2 = m;
    string res = "";
    while (1)
    {
        if (a[p1] == b[p2])
        {
            res += a[p1];
            --p1, --p2;
        }
        else if (dp[p1 - 1][p2] == dp[p1][p2])
            --p1;
        else
            --p2;
        if (res.size() == dp[n][m])
            break;
    }
    reverse(res.begin(), res.end());
    return res;
}
string f(string a)
{
    string res = "";
    for (int i = 0; i < a.size() - 1; i++)
    {
        string f1 = a.substr(0, i + 1);
        string f2 = a.substr(i + 1);
        if (get(f1, f2).size() > res.size())
            res = get(f1, f2);
    }
    return res;
}
int main()
{
    string a;
    while (cin >> a)
    {
        if (a[0] == '#')
            break;
        string ans = f(a);
        cout << ans << endl;
    }
    return 0;
}