Submission #944598

#	Time	Username	Problem	Language	Result	Execution time	Memory
944598		Nhoksocqt1	Longest Trip (IOI23_longesttrip)	C++17	5 / 100	3100 ms	480 KiB

longesttrip

#ifndef Nhoksocqt1
    #include "longesttrip.h"
#endif // Nhoksocqt1
#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 260;

#ifdef Nhoksocqt1

bitset<MAXN> adjp[MAXN], idA, idB, bsA, bsB;
struct Jury {
    int n, d;

    void init(int _n, int _d) {
        n = _n, d = _d;
        int u, v;
        bool check(0);
        while(cin >> u >> v) {
            adjp[u][v] = adjp[v][u] = 1;
            check = 1;
        }

        if(!check) {
            for (int i = 0; i < n; ++i) {
                for (int j = i + 1; j < n; ++j) {
                    for (int k = j + 1; k < n; ++k) {
                        int cnt = adjp[i][j] + adjp[i][k] + adjp[j][k];
                        if(cnt < d) {
                            vector<ii> p;
                            p.push_back(ii(i, j));
                            p.push_back(ii(i, k));
                            p.push_back(ii(j, k));

                            while(cnt < d) {
                                int r = Random(0, 2);
                                if(adjp[p[r].fi][p[r].se])
                                    continue;

                                ++cnt;
                                adjp[p[r].fi][p[r].se] = adjp[p[r].se][p[r].fi] = 1;
                            }
                        }
                    }
                }
            }
        }
    }

    bool are_connected(vector<int> &A, vector<int> &B) {
        bsA = bsB = idA = idB = 0;
        for (int it = 0; it < sz(A); ++it) {
            bsA |= adjp[A[it]];
            idA[A[it]] = 1;
        }

        for (int it = 0; it < sz(B); ++it) {
            bsB |= adjp[B[it]];
            idB[B[it]] = 1;
        }

        return ((bsA & idB).count() > 0 || (bsB & idA).count() > 0);
    }

} jury;

#endif // Nhoksocqt1

int numNode;
bool adj[MAXN][MAXN], dx[MAXN];

bool check_are_connected(vector<int> &A, vector<int> &B) {
    #ifdef Nhoksocqt1
        return jury.are_connected(A, B);
    #else
        return are_connected(A, B);
    #endif // Nhoksocqt1
}

int dfs(int u, int len, vector<int> &ans) {
    dx[u] = 1;
    if(len == numNode) {
        ans.push_back(u);
        return true;
    }

    for (int v = 0; v < numNode; ++v) {
        if(!dx[v] && adj[u][v]) {
            if(dfs(v, len + 1, ans)) {
                ans.push_back(u);
                return true;
            }
        }
    }

    dx[u] = 0;
}

int evaluation(int u) {
    vector<int> tmp;
    while(1) {
        dx[u] = 1;
        tmp.push_back(u);

        int maxLen(0), v(-1);
        for (int i = 0; i < numNode; ++i) {
            if(!dx[i] && adj[u][i]) {
                v = i;
                break;
            }
        }

        if(v < 0)
            break;

        u = v;
    }

    int res = sz(tmp);
    while(sz(tmp)) {
        dx[tmp.back()] = 0;
        tmp.pop_back();
    }

    return res;
}

int evaluation2(int u) {
    vector<int> tmp;
    while(1) {
        dx[u] = 1;
        tmp.push_back(u);

        int maxLen(0), v(-1);
        for (int i = 0; i < numNode; ++i) {
            if(!dx[i] && adj[u][i]) {
                int len = evaluation(i);
                if(maxLen < len) {
                    maxLen = len;
                    v = i;
                }
            }
        }

        if(v < 0)
            break;

        u = v;
    }

    int res = sz(tmp);
    while(sz(tmp)) {
        dx[tmp.back()] = 0;
        tmp.pop_back();
    }

    return res;
}

vector<int> longest_trip(int N, int D) {
    numNode = N;
    if(D == 3) {
        vector<int> ans;
        for (int i = 0; i < numNode; ++i)
            ans.push_back(i);

        return ans;
    }

    for (int u = 0; u < numNode; ++u) {
        for (int v = u + 1; v < numNode; ++v) {
            vector<int> A, B;
            A.push_back(u);
            B.push_back(v);
            adj[u][v] = adj[v][u] = check_are_connected(A, B);
        }
    }

    for (int i = 0; i < numNode; ++i)
        dx[i] = 0;

    vector<int> ans;
    int len(0), u(-1);
    for (int i = 0; i < numNode; ++i) {
        int z = evaluation2(i);
        if(len < z) {
            len = z;
            u = i;
        }
    }

    while(1) {
        dx[u] = 1;
        ans.push_back(u);

        int maxLen(0), v(-1);
        for (int i = 0; i < numNode; ++i) {
            if(!dx[i] && adj[u][i]) {
                int len = evaluation2(i);
                if(maxLen < len) {
                    maxLen = len;
                    v = i;
                }
            }
        }

        if(v < 0)
            break;

        u = v;
    }

    return ans;
}

#ifdef Nhoksocqt1

int main(void) {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    #define TASK "longesttrip"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    int n, d;
    cin >> n >> d;
    jury.init(n, d);

    vector<int> path = longest_trip(n, d);
    cout << "ANSWER: " << sz(path) << ": ";
    for (int it = 0; it < sz(path); ++it)
        cout << path[it] << ' '; cout << '\n';

    return 0;
}

#endif // Nhoksocqt1

Compilation message (stderr)

longesttrip.cpp: In function 'int evaluation(int)':
longesttrip.cpp:117:13: warning: unused variable 'maxLen' [-Wunused-variable]
  117 |         int maxLen(0), v(-1);
      |             ^~~~~~
longesttrip.cpp: In function 'int dfs(int, int, std::vector<int>&)':
longesttrip.cpp:108:11: warning: control reaches end of non-void function [-Wreturn-type]
  108 |     dx[u] = 0;
      |     ~~~~~~^~~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 60