Submission #1243419

#	Time	Username	Problem	Language	Result	Execution time	Memory
1243419		chr34	Round words (IZhO13_rowords)	C++20	44 / 100	2097 ms	484 KiB

rowords

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define endl "\n"
#define dbg(x) cout << #x << " = " << (x) << endl;
const int INF = 1e18;
const int MAXN = 1e6 + 10;
const int MOD = 1e9 + 7;

int lcs(const string& a, const string& b) {
    unordered_map<char, vector<int>> pos;
    for (int i = 0; i < (int)b.size(); ++i)
        pos[b[i]].push_back(i);

    vector<int> seq;
    for (char c : a) {
        if (pos.count(c)) {
            const vector<int>& indices = pos[c];
            for (int i = (int)indices.size() - 1; i >= 0; --i) {
                int idx = indices[i];
                auto it = lower_bound(seq.begin(), seq.end(), idx);
                if (it == seq.end())
                    seq.push_back(idx);
                else
                    *it = idx;
            }
        }
    }
    return (int)seq.size();
}

int32_t main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	//freopen("input.in", "r", stdin);
	//freopen("input.out", "w", stdout);    
	string s1, s2;
    cin >> s1 >> s2;

    int maxLCS = 0;
    string s1r = s1;
    reverse(s1r.begin(), s1r.end());

    string s2r = s2;
    reverse(s2r.begin(), s2r.end());

    string s2_doubled = s2 + s2;
    string s2r_doubled = s2r + s2r;
    int len = s2.size();

    for (int i = 0; i < len; ++i) {
        string rot_s2 = s2_doubled.substr(i, len);
        string rot_s2r = s2r_doubled.substr(i, len);
        maxLCS = max(maxLCS, lcs(s1, rot_s2));
        maxLCS = max(maxLCS, lcs(s1r, rot_s2));
        maxLCS = max(maxLCS, lcs(s1, rot_s2r));
        maxLCS = max(maxLCS, lcs(s1r, rot_s2r));
    }

    cout << maxLCS << endl;  
    return 0;
}

• Subtask 1: 44 / 100