Submission #255075

#	Time	Username	Problem	Language	Result	Execution time	Memory
255075		davitmarg	Graph (BOI20_graph)	C++17	100 / 100	198 ms	28112 KiB

Graph

/*
DavitMarg
In a honky-tonk,
Down in Mexico
*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <iomanip>
#include <bitset>
#include <stack>
#include <cassert>
#include <iterator>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin(), v.end()
#define fastIO ios::sync_with_stdio(false); cin.tie(0)
using namespace std;

const int N = 200005;

int n, m,used[N],d[N];
LD val, a[N];
vector<pair<int, int>> g[N];

vector<pair<int,LD>> vals;
set<LD> x;

void dfs(int v)
{
    vals.push_back(MP(v, a[v]));
    used[v] = 1;
    for (int i = 0; i < g[v].size(); i++)
    {
        int to = g[v][i].first;
        int val = g[v][i].second;
        if (used[to])
        {
            if (d[v] != d[to])
            {
                if (a[v] + a[to] != val)
                {
                    cout << "NO" << endl;
                    exit(0);
                }
            }
            else
            {
                LD X = (val - a[v] - a[to]) / 2.;
                if (d[v] == 0)
                    x.insert(X);
                else
                    x.insert(-X);
            }
            continue;
        }
        d[to] = d[v] ^ 1;
        a[to] = val - a[v];
        dfs(to);
    }
}

int main()
{
    fastIO;
    cin >> n >> m;
    while (m--)
    {
        int a, b, c;
        cin >> a >> b >> c;
        g[a].PB(MP(b, c));
        g[b].PB(MP(a, c));
    }
    for (int i = 1; i <= n; i++)
    {
        if (used[i])
            continue;
        x.clear();
        vals.clear();
        dfs(i);

        if (x.size() > 1)
        {
            cout << "NO" << endl;
            exit(0);
        }
        LD X = 0;
        if (!x.empty())
            X = *x.begin();
        else
        {
            for (int j = 0; j < vals.size(); j++)
                if (!d[vals[j].first])
                    vals[j].second *= -1;
            sort(all(vals), [](pair<int, LD> a, pair<int, LD> b) {
                return a.second < b.second;
            });
            X = vals[vals.size() / 2].second;
        }

        for (int j = 0; j < vals.size(); j++)
            if (!d[vals[j].first])
                a[vals[j].first] += X;
            else
                a[vals[j].first] -= X;
    }
    cout << "YES" << endl;
    for (int i = 1; i <= n; i++)
        cout << a[i] << " ";
    cout << endl;

    return 0;
}

/*


*/

Compilation message (stderr)

Graph.cpp: In function 'void dfs(int)':
Graph.cpp:45:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++)
                     ~~^~~~~~~~~~~~~
Graph.cpp: In function 'int main()':
Graph.cpp:104:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j = 0; j < vals.size(); j++)
                             ~~^~~~~~~~~~~~~
Graph.cpp:113:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < vals.size(); j++)
                         ~~^~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 12 / 12
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 42 / 42