oj.uz

Submission #289710

# Submission time Handle Problem Language Result Execution time Memory
289710 2020-09-02T23:17:23 Z ntfx timeismoney (balkan11_timeismoney) C++14
100 / 100
 885 ms 888 KB 
/*
    Problem: https://oj.uz/problem/view/balkan11_timeismoney

    Solution: http://www.boi2011.ro/resurse/tasks/timeismoney-sol.pdf
*/
#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
    #define D(a) cerr << #a << " = " << a << endl
#else 
    #define D(a) 8 
#endif
#define fastio ios_base::sync_with_stdio(0); cin.tie(0)
#define dforsn(i,s,n) for(int i=int(n-1);i>=int(s);i--)
#define forsn(i,s,n) for(int i=int(s);i<int(n);i++)
#define all(a) (a).begin(),(a).end()
#define dforn(i,n) dforsn(i,0,n)
#define forn(i,n) forsn(i,0,n)
#define si(a) int((a).size())
#define pb emplace_back
#define mp make_pair
#define snd second
#define fst first
#define endl '\n'
using pii = pair<int,int>;
using vi = vector<int>;
using ll = long long;

struct UF {
    vi par, sz;
    UF(int n): par(n), sz(n, 1) { iota(all(par), 0); }
    int find(int u) { return par[u] == u ? u : par[u] = find(par[u]); }
    bool connected(int u, int v) { return find(u) == find(v); }
    bool join(int u, int v) {
        if (connected(u, v)) return false;
        u = find(u), v = find(v);
        if (sz[u] < sz[v]) par[u] = v, sz[v] += sz[u];
        else par[v] = u, sz[u] += sz[v];
        return true;
    }
};

vi mst;
ll mn = 1e18;
int n, m, A, B, sumT, sumC;
vector<tuple<int,int,int,int>> edges;

struct Kruskal {
    vector<pii> ids;
    void addEdge(int cost, int id) { 
        ids.pb(cost, id); 
    }
    ll build() {
        sort(all(ids));
        mst.clear();
        UF uf(n);
        sumT = 0, sumC = 0;
        for (auto &[cst, id] : ids) {
            auto &[u, v, t, c] = edges[id];
            if (uf.join(u, v)) {
                mst.pb(id);
                sumT += t;
                sumC += c;
            }
        }
        ids.clear();
        return ll(sumT) * sumC;
    }
} kruskal;

struct Point {
    int x, y;
    bool collinear(const Point &p1, const Point &p2) {
        return ll(p2.y - p1.y) * (x - p1.x) == ll(y - p1.y) * (p2.x - p1.x);
    }
};

// Minimize a * sumT + b * sumC = v
Point optimize(int a, int b) { 
    forn(i, m) {
        auto &[u, v, t, c] = edges[i];
        kruskal.addEdge(a*t + b*c, i);
    }
    ll val = kruskal.build();
    if (val < mn) {
        mn = val;
        A = a, B = b;
    }
    return {sumC, sumT};
}

void computeConvexHull(const Point &p1, const Point &p2) {
    Point p = optimize(p2.x - p1.x, p1.y - p2.y);
    if (p.collinear(p1, p2)) return;
    computeConvexHull(p1, p), computeConvexHull(p, p2);
}

int main() {
	fastio;
	
    cin >> n >> m;
    edges.resize(m);
    for (auto &[u, v, t, c] : edges)
        cin >> u >> v >> t >> c;

    computeConvexHull(optimize(0, 1), optimize(1, 0));

    optimize(A, B); 
    cout << sumT << ' ';
    cout << sumC << endl;
    for (int id : mst) {
        auto &[u, v, t, c] = edges[id];
        cout << u << ' ' << v << endl;
    }
	return 0;
}

Compilation message

timeismoney.cpp: In member function 'll Kruskal::build()':
timeismoney.cpp:59:20: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   59 |         for (auto &[cst, id] : ids) {
      |                    ^
timeismoney.cpp:60:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   60 |             auto &[u, v, t, c] = edges[id];
      |                   ^
timeismoney.cpp: In function 'Point optimize(int, int)':
timeismoney.cpp:82:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   82 |         auto &[u, v, t, c] = edges[i];
      |               ^
timeismoney.cpp: In function 'int main()':
timeismoney.cpp:104:16: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  104 |     for (auto &[u, v, t, c] : edges)
      |                ^
timeismoney.cpp:113:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  113 |         auto &[u, v, t, c] = edges[id];
      |               ^

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 288 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 2 ms 384 KB Output is correct
8 Correct 7 ms 768 KB Output is correct
9 Correct 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 6 ms 384 KB Output is correct
15 Correct 4 ms 384 KB Output is correct
16 Correct 95 ms 384 KB Output is correct
17 Correct 100 ms 384 KB Output is correct
18 Correct 100 ms 632 KB Output is correct
19 Correct 874 ms 888 KB Output is correct
20 Correct 885 ms 888 KB Output is correct