Submission #914920

#	Time	Username	Problem	Language	Result	Execution time	Memory
914920		asdasdqwer	Graph (BOI20_graph)	C++14	100 / 100	353 ms	36604 KiB

Graph

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

#define int int64_t
#define pii pair<int, int>
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define unas mp(1e9, 1e9)
#define undef 1e15

bool contradiction = false;

struct Node {
    int index;
    set<pii> neigh;
    pii exp = unas;
    double minVal = undef;
};

bool operator==(const pii &x1, const pii &x2) {
    return x1.f == x2.f && x1.s == x2.s;
}

bool operator!=(const pii &x1, const pii &x2) {
    return x1.f != x2.f || x1.s != x2.s;
}

pii operator+(const pii &x1, const pii &x2) {
    return mp(x1.f+x2.f, x1.s+x2.s);
}

int conv(const pii &x) {
    if (x.f <= 0) return x.s;
    else return -x.s;
}

void pPair(const pii &x) {
    cout << x.f << " " << x.s << "\n";
}

void assignExp(vector<Node> &g, int idx) {
    g[idx].exp = mp(1, 0);
    // bfs
    queue<int> q;
    q.push(idx);
    while (!q.empty()) {
        int t=q.front();q.pop();
        pii ex = g[t].exp;
        for (pii x : g[t].neigh) {
            if (g[x.f].exp != unas) continue;
            g[x.f].exp = mp(-ex.f, x.s - ex.s);
            q.push(x.f);
        }
    }

    double search = 1e15;
    q.push(idx);
    vector<bool> v((int)g.size(), false);
    v[idx]=true;
    while (!q.empty()) {
        int t=q.front();q.pop();
        pii ex = g[t].exp;
        for (pii x : g[t].neigh) {
            if ((ex + g[x.f].exp).first != 0) {
                // cout << t << " " << x.f << "\n";
                // pPair(ex);pPair(g[x.f].exp);
                pii res = ex + g[x.f].exp;
                double lft = (double)x.s;
                lft -= (double)res.s;
                search = lft / (double)res.f;

                while (!q.empty())q.pop();
                break;
            }

            else if (!v[x.f]) {
                v[x.f]=true;
                q.push(x.f);
            }
        }
    }

    if (search == 1e15) {
        q.push(idx);
        vector<bool> visited((int)g.size(), false);
        visited[idx]=true;
        vector<int> coeff;
        coeff.pb(conv(g[idx].exp));
        while (!q.empty()) {
            int t=q.front();q.pop();
            for (pii x : g[t].neigh) {
                if (!visited[x.f]) {
                    visited[x.f]=true;
                    coeff.pb(conv(g[x.f].exp));
                    q.push(x.f);
                }
            }
        }

        sort(coeff.begin(), coeff.end());
        search = (double)coeff[(int)coeff.size()/2];
    }

    q.push(idx);
    g[idx].minVal = search;
    while (!q.empty()) {
        int t=q.front();q.pop();
        for (pii x : g[t].neigh) {
            if (g[x.f].minVal == undef) {
                g[x.f].minVal = (double)(g[x.f].exp.f) * search + (double)g[x.f].exp.s;
                q.push(x.f);
            }
        }
    }

    q.push(idx);
    vector<bool> visited((int)g.size(), false);
    while (!q.empty()) {
        int t=q.front();q.pop();
        for (pii x : g[t].neigh) {
            if (g[t].minVal + g[x.f].minVal != (double)x.s) contradiction = true;
            // printf("case %ld %ld\n", t, x.f);
            // printf("value of first : %lf, value of second : %lf, value of edge : %ld\n\n", g[t].minVal, g[x.f].minVal, x.s);
            if (!visited[x.f]) {
                visited[x.f]=true;
                q.push(x.f);
            }
        }
    }
}

signed main() {
    ios::sync_with_stdio(false);cin.tie(0);
    int n, m;cin>>n>>m;
    vector<Node> g(n);

    for (int i=0;i<n;i++) {
        g[i].index = i;
    }

    for (int i=0;i<m;i++) {
        int start, end, code;
        cin >> start >> end >> code;

        start--;end--;
        if (g[start].neigh.find(mp(end, 3 - code)) != g[start].neigh.end()) {
            cout << "NO\n";
            return 0;
        }

        g[start].neigh.insert(mp(end, code));
        g[end].neigh.insert(mp(start, code));
    }

    for (int i=0;i<n;i++) {
        if (g[i].exp == unas) {
            assignExp(g, i);
            if (contradiction) {
                cout << "NO\n";
                return 0;
            }
        }
    }

    if (contradiction) {
        cout << "NO\n";
        return 0;
    }

    cout << "YES\n";
    cout << g[0].minVal;

    for (int i=1;i<n;i++) {
        cout << " " << g[i].minVal;
    }

    cout << "\n";
}

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