Submission #550876

#	Time	Username	Problem	Language	Result	Execution time	Memory
550876		Zhora_004	Graph (BOI20_graph)	C++17	58 / 100	1049 ms	19016 KiB

Graph

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <unordered_set>
#include <queue>
#include <deque>
#include <string>
#include <sstream>
#include <iomanip>
#include <map>
#include <unordered_map>
#include <stack>
#include <cstdio>
#include <climits>
#include <tuple>
#include <ctime>
#include <cstring>
#include <numeric>
#include <functional>
#include <chrono>
#include <cassert>
#include <bitset>
#include <fstream>
//#include <bit>
//#include <ranges>
//#include <numbers>
#define itn int
#define sacnf scanf
#define sz(a) ((int)((a).size()))
// printf("%.10f\n", ans);
/*ofstream fout("timeline.out");
ifstream fin("timeline.in");*/
using ll = long long;
using namespace std;
const ll mod = 1e9 + 7;
const int limit = 170;
const int N = 2e5 + 1, inf = 1e9;

struct Edge {
    int v, w;
};

int n, m;
vector<bool> vis;
vector<int> comp, ans;
vector<vector<Edge>> gp;

void dfs1(int u)
{
    vis[u] = 1;
    comp.push_back(u);
    for (Edge& e : gp[u]) if (!vis[e.v]) dfs1(e.v);
}

void dfs2(int u, int val)
{
    vis[u] = 1;
    ans[u] = val;
    for (Edge& e : gp[u]) if (!vis[e.v]) dfs2(e.v, e.w - val);
}

int ok()
{
    int sum = 0;
    for (int& u : comp)
    {
        for (Edge& e : gp[u])
        {
            int v = e.v, w = e.w;
            if (!(-limit <= ans[u] && ans[u] <= limit && -limit <= ans[v] && ans[v] <= limit && ans[u] + ans[v] == w)) return inf;
        }
        sum += abs(ans[u]);
    }
    return sum;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> m;
    vis = vector<bool>(n);
    ans = vector<int>(n);
    gp = vector<vector<Edge>>(n);
    for (int i = 0; i < m; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        gp[--u].push_back({ --v, w * 2 });
        gp[v].push_back({ u, w * 2 });
    }
    for (int i = 0; i < n; i++)
    {
        if (!vis[i])
        {
            comp.clear();
            dfs1(i);
            int mn = inf, num = inf;
            for (int val = -limit; val <= limit; val++)
            {
                for (int& u : comp) vis[u] = 0;
                queue<int> q;
                q.push(i);
                vis[i] = 1;
                ans[i] = val;
                int sum = abs(val);
                while (!q.empty())
                {
                    int u = q.front();
                    q.pop();
                    for (Edge& e : gp[u])
                    {
                        int v = e.v, w = e.w;
                        if (!vis[v])
                        {
                            vis[v] = 1;
                            ans[v] = w - ans[u];
                            q.push(v);
                            if (ans[v] < -limit || ans[v] > limit)
                            {
                                sum = inf;
                                break;
                            }
                            sum += abs(ans[v]);
                        }
                        else if (ans[u] + ans[v] != w)
                        {
                            sum = inf;
                            break;
                        }
                    }
                    if (sum == inf) break;
                }
                if (sum < mn) mn = sum, num = val;
            }
            if (num == inf) return cout << "NO", 0;
            for (int& u : comp) vis[u] = 0;
            queue<int> q;
            q.push(i);
            vis[i] = 1;
            ans[i] = num;
            while (!q.empty())
            {
                int u = q.front();
                q.pop();
                for (Edge& e : gp[u])
                {
                    int v = e.v, w = e.w;
                    if (!vis[v])
                    {
                        vis[v] = 1;
                        ans[v] = w - ans[u];
                        q.push(v);
                    }
                }
            }
        }
    }
    cout << "YES\n";
    for (int& i : ans)
    {
        if (i == -1) cout << "-0.5";
        else
        {
            cout << i / 2;
            if (abs(i) & 1) cout << ".5";
        }
        cout << " ";
    }

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 12 / 12
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 0 / 42