Submission #1235493

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235493		k1r1t0	Longest Trip (IOI23_longesttrip)	C++20	85 / 100	11 ms	448 KiB

longesttrip

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

bool are_connected(vector<int> A, vector<int> B);

vector<int> longest_trip(int n, int d) {
	int state = 0;
	// 0 - path
	// 1 - cliques
	vector<int> a, b;
	a.push_back(0);
	for (int i = 1; i < n; i++) {
		if (state == 0) {
			bool al = are_connected({i}, {a.front()});
			if (al) {
				reverse(begin(a), end(a));
				a.push_back(i);
				continue;
			}
			bool ar = are_connected({i}, {a.back()});
			if (ar) {
				a.push_back(i);
				continue;
			}
			int l = 1, r = (int) a.size() - 1;
			while (l < r) {
				int mid = (l + r) / 2;
				vector<int> pref;
				for (int j = 0; j <= mid; j++)
					pref.push_back(a[j]);
				if (are_connected({i}, pref)) r = mid;
				else l = mid + 1;
			}
			if (l > r || l == (int) a.size() - 1) {
				b.push_back(i);
				state = 1;
				continue;
			}
			vector<int> c;
			for (int j = l + 1; j < (int) a.size(); j++)
				c.push_back(a[j]);
			for (int j = 0; j <= l; j++)
				c.push_back(a[j]);
			c.push_back(i);
			a = c;
			continue;
		}
		bool ta = are_connected({i}, a);
		bool tb = are_connected({i}, b);
		if (!ta) {
			b.push_back(i);
			continue;
		}
		if (!tb) {
			a.push_back(i);
			continue;
		}
		vector<int> c;
		int l = 0, r = (int) a.size() - 1;
		while (l < r) {
			int mid = (l + r) / 2;
			vector<int> pref;
			for (int j = 0; j <= mid; j++)
				pref.push_back(a[j]);
			if (are_connected({i}, pref)) r = mid;
			else l = mid + 1;
		}
		for (int j = l + 1; j < (int) a.size(); j++)
			c.push_back(a[j]);
		for (int j = 0; j <= l; j++)
			c.push_back(a[j]);
		c.push_back(i);
		l = 0, r = (int) b.size() - 1;
		while (l < r) {
			int mid = (l + r) / 2;
			vector<int> pref;
			for (int j = 0; j <= mid; j++)
				pref.push_back(b[j]);
			if (are_connected({i}, pref)) r = mid;
			else l = mid + 1;
		}
		for (int j = l; j < (int) b.size(); j++)
			c.push_back(b[j]);
		for (int j = 0; j < l; j++)
			c.push_back(b[j]);
		a = c;
		b.clear();
		state = 0;
	}
	if (a.size() > b.size())
		return a;
	return b;
}































/*

static inline constexpr int maxNumberOfCalls = 32640;
static inline constexpr int maxTotalNumberOfCalls = 150000;
static inline constexpr int maxTotalNumberOfLandmarksInCalls = 1500000;
static int call_counter = 0;
static int total_call_counter = 0;
static int landmark_counter = 0;

static int C, N, D;
static std::vector<std::vector<int>> U;
static std::vector<bool> present;

static inline void protocol_violation(std::string message)
{
    printf("Protocol Violation: %s\n", message.c_str());
    exit(0);
}

bool are_connected(std::vector<int> A, std::vector<int> B)
{
    ++call_counter;
    ++total_call_counter;
    if (call_counter > maxNumberOfCalls || total_call_counter > maxTotalNumberOfCalls)
    {
        protocol_violation("too many calls");
    }

    int nA = A.size(), nB = B.size();
    landmark_counter += nA + nB;
    if (landmark_counter > maxTotalNumberOfLandmarksInCalls)
    {
        protocol_violation("too many elements");
    }

    if (nA == 0 || nB == 0)
    {
        protocol_violation("invalid array");
    }
    for (int i = 0; i < nA; ++i)
    {
        if (A[i] < 0 || N <= A[i])
        {
            protocol_violation("invalid array");
        }
        if (present[A[i]])
        {
            protocol_violation("invalid array");
        }
        present[A[i]] = true;
    }
    for (int i = 0; i < nA; ++i)
    {
        present[A[i]] = false;
    }
    for (int i = 0; i < nB; ++i)
    {
        if (B[i] < 0 || N <= B[i])
        {
            protocol_violation("invalid array");
        }
        if (present[B[i]])
        {
            protocol_violation("invalid array");
        }
        present[B[i]] = true;
    }
    for (int i = 0; i < nB; ++i)
    {
        present[B[i]] = false;
    }

    for (int i = 0; i < nA; ++i)
    {
        for (int j = 0; j < nB; ++j)
        {
            if (A[i] == B[j])
            {
                protocol_violation("non-disjoint arrays");
            }
        }
    }

    for (int i = 0; i < nA; ++i)
    {
        for (int j = 0; j < nB; ++j)
        {
            if (U[std::max(A[i], B[j])][std::min(A[i], B[j])] == 1)
            {
                return true;
            }
        }
    }

    return false;
}

int main()
{
    assert(1 == scanf("%d", &C));
    int maximumCalls = 0;
    for (int c = 0; c < C; ++c)
    {
        call_counter = 0;
        assert(2 == scanf("%d %d", &N, &D));

        present.assign(N, false);
        U.resize(N);
        for (int i = 1; i < N; ++i)
        {
            U[i].resize(i);
            for (int j = 0; j < i; ++j)
            {
                assert(1 == scanf("%d", &U[i][j]));
            }
        }

        for (int i = 2; i < N; ++i)
        {
            for (int j = 1; j < i; ++j)
            {
                for (int k = 0; k < j; ++k)
                {
                    if (U[i][j] + U[i][k] + U[j][k] < D)
                    {
                        printf("Insufficient Density\n");
                        exit(0);
                    }
                }
            }
        }

        std::vector<int> t = longest_trip(N, D);
        int l = t.size();
        printf("%d\n", l);
        for (int i = 0; i < l; ++i)
        {
            printf(i == 0 ? "%d" : " %d", t[i]);
        }
        printf("\n");
        printf("%d\n", call_counter);

        maximumCalls = std::max(maximumCalls, call_counter);
        call_counter = 0;
    }
    printf("%d\n", maximumCalls);

    return 0;
}

//*/

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 45 / 60