题目描述

最长公共子序列 + Kruskal

C++ 代码

#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>

using namespace std;

int n, m;

const int N = 210;

string str[N];

vector<pair<int,pair<int, int>>>vec;

int dp[N][N];

int solveD(string A, string B)
{

    int res = 0;

    /*
        aabbaabb

        abbaabba
        accaacca
    */

    memset(dp, 0 ,sizeof dp);

    for (int i = 1; i < A.size(); i ++)
    {
        for (int j = 1; j < B.size(); j ++)
        {
            if ( A[i - 1] == B[j - 1]) {
                dp[i][j] = dp[i - 1][j - 1] + 1;
                res = max(dp[i][j],res);   
            }
        }

    }
    res = min(res, m);
    return res;
}

int p[N];

int find(int x)  // 并查集
{
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}


int main()
{
    cin >> n >> m;

    for (int i = 0; i < n; i ++) {
        cin >> str[i];
        str[i] = str[i] + str[i];
    }

    for (int i = 1;i <= n;i ++){
        p[i] = i;
    }

    for (int i = 0;i < n;i ++)
    {
        for (int j = i + 1;j < n;j ++) {
            int d = solveD(str[i],str[j]);
            // cout << d << endl;
            vec.push_back({d, {i, j}});
        }
    }

    sort(vec.begin(),vec.end(),[](pair<int,pair<int,int>>p1, pair<int,pair<int,int>>p2){
        return p1.first > p2.first;
    });

    int res = 0;

    for (int i = 0; i < vec.size();i ++)
    {
        int a = vec[i].second.first, b = vec[i].second.second;

        int p1 = find(a), p2 = find(b);
        if (p1 != p2) {
            res += vec[i].first;
            p[p2] = p1;
        }
    }

    cout << res << endl;

    return 0;
}