Submission #557631

#	Time	Username	Problem	Language	Result	Execution time	Memory
557631		Jomnoi	Graph (BOI20_graph)	C++17	100 / 100	160 ms	25408 KiB

Graph

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

const int MAX_N = 1e5 + 10;
const int INF = 1e9 + 7;

int cnt_component;
vector <pair <int, int>> graph[MAX_N];
vector <int> node[MAX_N];
int component[MAX_N];
int A[MAX_N], B[MAX_N];
double X[MAX_N];

void dfs(int u, int p, int now_component, int a, int b) {
    A[u] = a, B[u] = b;
    component[u] = now_component;
    node[now_component].push_back(u);
    for(auto [v, c] : graph[u]) {
        if(v == p) {
            continue;
        }

        int na = -a, nb = c - b;
        if(component[v] != 0) {
            if(A[v] == na) {
                if(B[v] != nb) {
                    cout << "NO";
                    exit(0);
                }
            }
            else {
                double x = 1.0 * (B[v] - nb) / (na - A[v]);
                if(X[now_component] != INF and X[now_component] != x) {
                    cout << "NO";
                    exit(0);
                }
                X[now_component] = x;
            }
        }
        else {
            dfs(v, u, now_component, na, nb);
        }
    }
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int N, M;
    cin >> N >> M;
    while(M--) {
        int a, b, c;
        cin >> a >> b >> c;
        graph[a].emplace_back(b, c);
        graph[b].emplace_back(a, c);
    }

    fill(X + 1, X + N + 1, INF);
    for(int i = 1; i <= N; i++) {
        if(component[i] != 0) {
            continue;
        }
        
        dfs(i, -1, ++cnt_component, 1, 0);

        if(X[cnt_component] == INF) {
            vector <int> median;
            for(auto v : node[cnt_component]) {
                median.push_back(-A[v] * B[v]);
            }

            sort(median.begin(), median.end());
            X[cnt_component] = median[median.size() / 2];
        }
    }

    cout << "YES\n";
    for(int i = 1; i <= N; i++) {
        cout << fixed << setprecision(9) << A[i] * X[component[i]] + B[i] << ' ';
    }
    return 0;
}

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