Submission #1014855

#	Time	Username	Problem	Language	Result	Execution time	Memory
1014855		alex_2008	Split the Attractions (IOI19_split)	C++14	18 / 100	562 ms	1048576 KiB

split

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

typedef long long ll;
const int N = 1e5 + 10;

bool used[N];
int subtree[N];
int par[N];
vector<vector<int>> G;
int sz;
vector<int> esim;

void dfs(int v) {
    if (used[v]) return;
    if ((int)esim.size() == sz) return;
    esim.push_back(v);
    used[v] = true;
    for (auto it : G[v]) {
        dfs(it);
    }
}

void dfss(int v, int p) {
    par[v] = p;
    subtree[v] = 1;
    for (auto it : G[v]) {
        if (it == p) continue;
        dfss(it, v);
        subtree[v] += subtree[it];
    }
}

vector<int> find_split(int n, int A, int B, int C, vector<int> p, vector<int> q) {
    int m = (int)p.size();
    bool sb1 = true, sb2 = true;
    G.resize(n);
    for (int i = 0; i < m; i++) {
        G[p[i]].push_back(q[i]);
        G[q[i]].push_back(p[i]);
    }

    for (int i = 0; i < n; i++) {
        if ((int)G[i].size() > 2) sb1 = false;
    }

    if (sb1) {
        int a = -1, b = -1;
        for (int i = 0; i < n; i++) {
            if ((int)G[i].size() == 1) {
                if (a == -1) a = i;
                else b = i;
            }
        }
        if (a == -1) a = 0;
        vector<int> v;
        v.push_back(a);
        v.push_back(G[a][0]);
        while ((int)v.size() < n) {
            int a = v[(int)v.size() - 1];
            int b = v[(int)v.size() - 2];
            if (G[a][0] == b) v.push_back(G[a][1]);
            else v.push_back(G[a][0]);
        }
        vector<int> ans(n);
        for (int i = 0; i < n; i++) {
            if (i < A) ans[v[i]] = 1;
            else if (i < A + B) ans[v[i]] = 2;
            else ans[v[i]] = 3;
        }
        return ans;
    }

    sb2 = (A == 1);
    if (sb2) {
        sz = B;
        dfs(0);
        vector<int> ans(n);
        bool al = true;
        for (int i = 0; i < n; i++) {
            if (used[i]) ans[i] = 2;
            else {
                if (al) {
                    al = false;
                    ans[i] = 1;
                }
                else ans[i] = 3;
            }
        }
        return ans;
    }

    vector<pair<int, int>> v = { { A, 1 }, { B, 2 }, { C, 3 } };
    sort(v.begin(), v.end());
    dfss(0, 0);
    bool ch = true;

    if (ch) {
        set<pair<int, int>> candidates;
        for (auto it : G[0]) {
            candidates.insert({ subtree[it], it });
        }
        vector<int> f = { 0 };
        int cur_sz = 1;
        while (cur_sz < v[0].first) {
            auto it = candidates.begin();
            int v = it->second;
            f.push_back(v);
            for (auto it : G[v]) {
                if (it == par[v]) continue;
                candidates.insert({ subtree[it], it });
            }
            cur_sz++;
        }
        auto it = candidates.end(); it--;
        if (it->first >= v[1].first) {
            vector<int> ans(n, 0);
            esim.clear();
            for (int i = 0; i < n; i++) {
                used[i] = false;
            }
            int w = it->second;
            sz = v[1].first;
            used[par[w]] = true;
            dfs(w);
            for (auto& it : f) {
                ans[it] = v[0].second;
            }
            for (auto& it : esim) {
                ans[it] = v[1].second;
            }
            for (auto& it : ans) {
                if (it == 0) it = v[2].second;
            }
            return ans;
        }
    }

    swap(v[0], v[1]);
    if (ch) {
        set<pair<int, int>> candidates;
        for (auto it : G[0]) {
            candidates.insert({ subtree[it], it });
        }
        vector<int> f = { 0 };
        int cur_sz = 1;
        while (cur_sz < v[0].first) {
            auto it = candidates.begin();
            int v = it->second;
            f.push_back(v);
            for (auto it : G[v]) {
                if (it == par[v]) continue;
                candidates.insert({ subtree[it], it });
            }
            cur_sz++;
        }
        auto it = candidates.end(); it--;
        if (it->first >= v[1].first) {
            vector<int> ans(n, 0);
            esim.clear();
            for (int i = 0; i < n; i++) {
                used[i] = false;
            }
            int w = it->second;
            sz = v[1].first;
            used[par[w]] = true;
            dfs(w);
            for (auto& it : f) {
                ans[it] = v[0].second;
            }
            for (auto& it : esim) {
                ans[it] = v[1].second;
            }
            for (auto& it : ans) {
                if (it == 0) it = v[2].second;
            }
            return ans;
        }
    }

    vector<int> ans(n, 0);
    return ans;
}
/*
int main() {
    vector<int> p, q;
    int n, a, b, c;
    cin >> n >> a >> b >> c;
    for (int i = 1; i < n; i++) {
        int x, y;
        cin >> x >> y;
        p.push_back(x);
        q.push_back(y);
    }
    vector<int> qwe = find_split(n, a, b, c, p, q);
    for (auto it : qwe) {
        cout << it << " ";
    }
}
*/

Compilation message (stderr)

split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:51:21: warning: variable 'b' set but not used [-Wunused-but-set-variable]
   51 |         int a = -1, b = -1;
      |                     ^

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