Submission #1242981

#	Time	Username	Problem	Language	Result	Execution time	Memory
1242981		ericl23302	Sphinx's Riddle (IOI24_sphinx)	C++20	36 / 100	31 ms	412 KiB

sphinx

#include "sphinx.h"
#include <bits/stdc++.h> 

using namespace std;

void dfs(int cur, vector<bool> &visited, vector<vector<int>> &adjacency, int erased) {
    visited[cur] = true;
    for (auto &i : adjacency[cur]) {
        if (visited[i] || i == erased) continue;
        dfs(i, visited, adjacency, erased);
    }
}

int countComponents(int erased, int N, vector<vector<int>> &adjacency) {
    vector<bool> visited(N, false);
    int cnt = 1;
    for (int i = 0; i < N; ++i) {
        if (visited[i] || i == erased) continue;
        dfs(i, visited, adjacency, erased);
        ++cnt;
    }
    return cnt;
}

void findColours(vector<int> &G, int N, int mod) {
    vector<bool> erased(N / 2, false);
    for (int colour = 0; colour < N; ++colour) {
        // cout << "COLOUR: " << colour << endl;
        bool done = true;
        for (int i = 0; i < N / 2; ++i) {
            if (!erased[i]) {
                done = false;
                break;
            }
        }
        if (done) return;

        vector<int> E(N, N);
        for (int i = 0; i < N / 2; ++i) {
            if (erased[i]) continue;
            E[i * 2 + mod] = -1;
            E[i * 2 + 1 - mod] = colour;
        }

        int expected = 0;
        int cur = -10;
        for (int i = 0; i < N; ++i) {
            if (E[i] != cur) ++expected;
            cur = E[i];
        }

        // for (int &i : E) cout << i << ' ';
        // cout << endl;
        // cout << "EXPECTED: " << expected << endl;

        if (perform_experiment(E) == expected) continue;

        // cout << "FOUND SOMETHING" << endl;

        int remainCount = 0;
        for (int i = 0; i < N / 2; ++i) {
            if (erased[i]) continue;
            ++remainCount;
        }

        // cout << "REMAINING: " << remainCount << endl;

        int left = 0, right = remainCount;
        while (left < right - 1) {
            // cout << "BIN: " << left << ' ' << right << endl;
            int mid = (left + right) / 2;
            // cout << "MID: " << mid << endl;
            E.assign(N, N);
            int cur = 0;
            for (int i = 0; i < N / 2; ++i) {
                if (cur == mid) break;
                if (erased[i]) continue;
                if (cur >= left) {
                    E[i * 2 + mod] = -1;
                    E[i * 2 + 1 - mod] = colour;
                }
                ++cur;
            }

            int expected = 0;
            cur = -10;
            for (int i = 0; i < N; ++i) {
                if (E[i] != cur) ++expected;
                cur = E[i];
            }

            // for (int &i : E) cout << i << ' ';
            // cout << endl;
            // cout << "EXPECTED: " << expected << endl;

            if (perform_experiment(E) < expected) right = mid;
            else left = mid;
        }

        // cout << "BIN DONE WITH LEFT: " << left << endl;

        cur = 0;
        for (int i = 0; i < N / 2; ++i) {
            if (erased[i]) continue;
            if (cur == left) {
                // cout << "FOUND THAT " << i * 2 + mod << " HAS COLOUR " << colour << endl;
                G[i * 2 + mod] = colour;
                erased[i] = true;
                break;
            }
            ++cur;
        }

        --colour;
    }
}

std::vector<int> find_colours(int N, std::vector<int> X, std::vector<int> Y) {
    vector<int> G(N, -1);
    // vector<vector<int>> adjacency(N);
    // for (int i = 0; i < X.size(); ++i) {
    //     adjacency[X[i]].push_back(Y[i]);
    //     adjacency[Y[i]].push_back(X[i]);
    // }
    findColours(G, N, 0);
    findColours(G, N, 1);
    if (N % 2) {
        vector<int> E(N, N);
        E[N - 1] = -1;
        for (int colour = 0; colour < N; ++colour) {
            E[N - 2] = colour;
            if (perform_experiment(E) < 3) {
                G[N - 1] = colour;
                break;
            }
        }
    }

    return G;
}

• Subtask 0: 0 / 0
• Subtask 1: 3 / 3
• Subtask 2: 0 / 7
• Subtask 3: 33 / 33
• Subtask 4: 0 / 21
• Subtask 5: 0 / 36