Submission #1279408

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279408		lightentheshadow	Split the Attractions (IOI19_split)	C++20	100 / 100	72 ms	27052 KiB

split

#include "split.h"
#include <bits/stdc++.h>
using namespace std;

const int maxN = 1e5 + 5;
vector<int> adj[maxN], graph[maxN];
int in[maxN], out[maxN], sz[maxN], arr[maxN], par[maxN], timeDfs = 0;

void dfsTree(int u) {
    in[u] = ++timeDfs; arr[timeDfs] = u;
    sz[u] = 1;
    for (auto v: adj[u]) {
        if (sz[v]) continue;
        graph[u].push_back(v);
        par[v] = u;
        dfsTree(v);
        sz[u] += sz[v];
    }
    out[u] = timeDfs;
}

bool inside[maxN];
int done[maxN];
int require;
vector<int> save;
void dfsNode(int u) {
    if (require > save.size()) save.push_back(u);
    done[u] = 1;

    for (auto v: adj[u]) {
        if (done[v]) continue;
        dfsNode(v);
    }
}

vector<int> find_split(int n, int A, int B, int C, vector<int> U, vector<int> V) {
    int m = U.size();

    for (int i = 0; i < m; i++) {
        adj[U[i]].push_back(V[i]);
        adj[V[i]].push_back(U[i]);
    }

    dfsTree(0);

    int a = min({A, B, C}), c = max({A, B, C}), b = A + B + C - a - c;
    int node = 0;

    for (int i = 0; i < n; i++) {
        if (sz[i] < a) continue;
        bool kt = true;
        for (auto x: graph[i])
            if (sz[x] >= a) kt = false;
        if (kt) {
            node = i;
            break;
        }
    }

    for (int i = in[node]; i <= out[node]; i++)
        inside[arr[i]] = true;

    for (int i = in[node]; i <= out[node]; i++) {
        int u = arr[i];
        if (!inside[u]) continue;
        bool kt = false;
        for (auto v: adj[u])
            if (!inside[v]) {
                kt = true;
                break;
            }

        if (!kt) continue;
        if (sz[node] - sz[u] >= a) {
            for (int j = in[u]; j <= out[u]; j++)
                inside[arr[j]] = false;
            sz[node] -= sz[u];
        }
    }

    vector<int> ans(n, 0);
    if (n - sz[node] < a) return ans;
    if (sz[node] < n - sz[node]) {
        save.clear();
        for (int i = 0; i < n; i++)
            if (!inside[i]) done[i] = 1;
                else done[i] = 0;
        require = a;
        dfsNode(node);
        for (auto x: save)
            ans[x] = 1;

        save.clear();
        for (int i = 0; i < n; i++)
            if (inside[i]) done[i] = 1;
                else done[i] = 0;
        require = b;
        dfsNode(par[node]);
        for (auto x: save)
            ans[x] = 2;

        for (int i = 0; i < n; i++)
            if (ans[i] == 0) ans[i] = 3;
    }
    else {
        save.clear();
        for (int i = 0; i < n; i++)
            if (!inside[i]) done[i] = 1;
                else done[i] = 0;
        require = b;
        dfsNode(node);
        for (auto x: save)
            ans[x] = 2;

        save.clear();
        for (int i = 0; i < n; i++)
            if (inside[i]) done[i] = 1;
                else done[i] = 0;
        require = a;
        dfsNode(par[node]);
        for (auto x: save)
            ans[x] = 1;

        for (int i = 0; i < n; i++)
            if (ans[i] == 0) ans[i] = 3;
    }

    int Swap[4];
    if (a == A) Swap[1] = 1;
        else if (a == B) Swap[1] = 2;
            else Swap[1] = 3;

    if (b == A && Swap[1] != 1) Swap[2] = 1;
        else if (b == B && Swap[1] != 2) Swap[2] = 2;
            else Swap[2] = 3;

    Swap[3] = 6 - Swap[1] - Swap[2];

    for (int i = 0; i < n; i++)
        ans[i] = Swap[ans[i]];

    return ans;
}

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