Submission #766716

#	Time	Username	Problem	Language	Result	Execution time	Memory
766716		t6twotwo	Split the Attractions (IOI19_split)	C++17	40 / 100	59 ms	25644 KiB

split

#include "split.h"
#include <bits/stdc++.h>
using namespace std;
vector<int> find_split(int n, int a, int b, int c, vector<int> p, vector<int> q) {
    int m = p.size();
    vector<vector<int>> adj(n);
    for (int i = 0; i < m; i++) {
        adj[p[i]].push_back(q[i]);
        adj[q[i]].push_back(p[i]);
    }
    vector<int> ans(n);
    auto F = [&](int s, int t, int p, int c, int b) {
        queue<int> q;
        q.push(s);
        ans[s] = c;
        int cnt = 1;
        while (!q.empty()) { 
            int x = q.front();
            q.pop();
            for (int y : adj[x]) {
                if (y != b && ans[y] == p  && cnt < t) {
                    cnt++;
                    ans[y] = c;
                    q.push(y);
                }
            }
        }
    };
    if (a == 1) {
        ans = vector<int>(n, 3);
        F(0, b, 3, 2, -1);
        for (int i = 0; i < n; i++) {
            if (ans[i] == 3) {
                ans[i] = 1;
                break;
            }
        }
        return ans;
    }
    if (m == n - 1) {
        auto dfs = [&](auto dfs, int x, int p) -> int {
            int sz = 1;
            for (int y : adj[x]) {
                if (y == p) {
                    continue;
                }
                int t = dfs(dfs, y, x);
                if (t == -1) {
                    return -1;
                }
                sz += t;
            }
            bool u = sz >= a && n - sz >= min(b, c);
            bool v = sz >= b && n - sz >= min(a, c);
            bool w = sz >= c && n - sz >= min(a, b);
            int T[3], S[4] = {0, a, b, c};
            if (u || v || w) {
                if (u) {
                    T[0] = 1;
                    if (n - sz >= b) {
                        T[1] = 2;
                        T[2] = 3;
                    } else {
                        T[1] = 3;
                        T[2] = 2;
                    }
                } else if (v) {
                    T[0] = 2;
                    if (n - sz >= a) {
                        T[1] = 1;
                        T[2] = 3;
                    } else {
                        T[1] = 3;
                        T[2] = 1;
                    }
                } else {
                    T[0] = 3;
                    if (n - sz >= a) {
                        T[1] = 1;
                        T[2] = 2;
                    } else {
                        T[1] = 2;
                        T[2] = 1;
                    }
                }
                ans = vector<int>(n, T[2]);
                F(x, S[T[0]], T[2], T[0], p);
                F(p, S[T[1]], T[2], T[1], x);
                return -1;
            }
            return sz;
        };
        if (dfs(dfs, 0, -1) == -1) {
            return ans;
        } else {
            return vector<int>(n);
        }
    }
    ans = vector<int>(n, 3);
    int s = 0;
    for (int i = 0; i < n; i++) {
        if (adj[i].size() == 1) {
            s = i;
            break;
        }
    }
    F(s, a, 3, 1, -1);
    for (int i = 0; i < n; i++) {
        if (ans[i] == 3) {
            F(i, b, 3, 2, -1);
            return ans;
        }
    }
    return vector<int>(n);
}

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36