Submission #837657

#	Time	Username	Problem	Language	Result	Execution time	Memory
837657		Desh03	Split the Attractions (IOI19_split)	C++17	0 / 100	1 ms	212 KiB

split

#include "split.h"

#include <bits/stdc++.h>

using namespace std;

struct DSU {
    vector<int> f, sz;
    DSU(const int &n) {
        f.resize(n), sz.resize(n, 1);
        iota(f.begin(), f.end(), 0);
    }
    int find(const int &u) {
        return u == f[u] ? u : f[u] = find(f[u]);
    }
    bool unite(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return 0;
        if (sz[u] < sz[v]) swap(u, v);
        sz[u] += sz[v], f[v] = u;
        return 1;
    }
};

vector<vector<int>> g;
vector<int> sz, par, col;
vector<pair<int, int>> f(3);
int x, w, cnt, cnt2;

void dfs(int u) {
    sz[u] = 1;
    for (int v : g[u]) {
        if (v != par[u]) {
            par[v] = u;
            dfs(v);
            sz[u] += sz[v];
        }
    }
    if (sz[u] >= f[0].first && sz[u] < x) {
        x = sz[u];
        w = u;
    }
}

void dfs2(int u) {
    if (cnt < f[0].first) {
        cnt++;
        col[u] = f[0].second;
    } else {
        col[u] = f[2].second;
    }
    for (int v : g[u]) {
        if (v != par[u]) {
            dfs2(v);
        }
    }
}

void dfs3(int u) {
    if (cnt < f[1].first) {
        cnt++;
        col[u] = f[1].second;
    } else {
        col[u] = f[2].second;
    }
    for (int v : g[u]) {
        if (v != w && v != par[u]) {
            dfs3(v);
        }
    }
}

vector<int> find_split(int root) {
    w = root, cnt = 0, x = g.size() + 1;
    par[root] = root;
    dfs(root);
    if (w == root) return vector<int> (g.size());
    dfs2(w);
    cnt = 0;
    dfs3(root);
    if (cnt != f[1].second) return vector<int> (g.size());
    return col;
}

vector<int> find_split(int n, int a, int b, int c, vector<int> p, vector<int> q) {
    f[0] = {a, 1}, f[1] = {b, 2}, f[2] = {c, 3}, x = n + 1, cnt = cnt2 = w = 0;
    sort(f.begin(), f.end());
    g = vector<vector<int>> (n), sz = par = col = vector<int> (n);
    DSU ds(n);
    for (int i = 0; i < p.size(); i++) {
        if (ds.unite(p[i], q[i])) {
            g[p[i]].push_back(q[i]);
            g[q[i]].push_back(p[i]);
        }
    }
    for (int i = 0; i < n; i++) {
        if (find_split(i) != vector<int> (n)) return col;
    }
    return vector<int> (n);
}

Compilation message (stderr)

split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:90:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |     for (int i = 0; i < p.size(); i++) {
      |                     ~~^~~~~~~~~~

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