Submission #772799

#	Time	Username	Problem	Language	Result	Execution time	Memory
772799		fve5	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	156 ms	24052 KiB

supertrees

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

struct DSU {
    vector<int> nodes;

    int find(int node) {
        if (nodes[node] < 0) return node;
        return nodes[node] = find(nodes[node]);
    }

    void join(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return;

        if (nodes[u] > nodes[v]) swap(u, v);
        nodes[u] += nodes[v];
        nodes[v] = u;
    }

    map<int, vector<int>> get_cc() {
        map<int, vector<int>> ans;
        for (int i = 0; i < nodes.size(); i++) {
            ans[find(i)].push_back(i);
        }
        return ans;
    }

    DSU(int size) : nodes(size, -1) { }
};

int construct(vector<vector<int>> p) {
    int n = p.size();
    DSU dsu(n);
    vector<vector<int>> adj(n, vector<int>(n, 0));
    
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            if(p[i][j]) dsu.join(i, j);
        }
    }

    map<int, vector<int>> ccs = dsu.get_cc();
    for (auto [_, cc]: ccs) {
        for (int i = 1; i < cc.size(); i++) {
            adj[cc[i - 1]][cc[i]] = adj[cc[i]][cc[i - 1]] = 1;
        }
    }
    build(adj);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In member function 'std::map<int, std::vector<int> > DSU::get_cc()':
supertrees.cpp:24:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         for (int i = 0; i < nodes.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:46:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         for (int i = 1; i < cc.size(); i++) {
      |                         ~~^~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 0 / 10
• Subtask 3: 0 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4