Submission #1237873

#	Time	Username	Problem	Language	Result	Execution time	Memory
1237873		Icelast	timeismoney (balkan11_timeismoney)	C++20	0 / 100	1 ms	328 KiB

timeismoney

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
struct DSU{
    int n;
    vector<int> pa, sz;
    DSU(int n) : n(n){
        pa.resize(n+1);
        sz.resize(n+1, 1);
        for(int i = 0; i <= n; i++){
            pa[i] = i;
        }
    };
    int find(int x){
        while(x != pa[x]){
            x = pa[x] = pa[pa[x]];
        }
        return x;
    }
    bool same(int x, int y){
        return find(x) == find(y);
    }
    bool merge(int x, int y){
        x = find(x);
        y = find(y);
        if(x == y) return false;
        if(sz[x] < sz[y]) swap(x, y);
        pa[y] = x;
        sz[x] += sz[y];
        return true;
    }
    int size(int x){
        return sz[find(x)];
    }
};

struct edge{
    int u, v, t, c;
};
struct mst{
    ll SumTime, SumMoney;
    vector<pair<int, int>> e;
};
void solve(){
    int n, m;
    cin >> n >> m;
    vector<edge> edges(m+1);
    for(int i = 1; i <= m; i++){
        int u, v, t, c;
        cin >> u >> v >> t >> c;
        edges[i] = {u, v, t, c};
    }
    //https://dmoj.ca/problem/bkoi11p5/editorial
    vector<mst> Convex_Hull;
    auto get_mst = [&](ll a, ll b) -> mst{ // get the mst with minimum at + bc (in other words slope -a/b)
        mst res;
        res.SumTime = 0, res.SumMoney = 0;
        vector<edge> e = edges;
        sort(e.begin()+1, e.end(), [&](edge x, edge y){return x.t*a + x.c*b < y.t*a + y.c*b;});
        DSU dsu(n+1);
        for(int i = 1; i <= m; i++){
            if(dsu.merge(e[i].u, e[i].v)){
                res.SumTime += e[i].t;
                res.SumMoney += e[i].c;
                res.e.push_back({e[i].u, e[i].v});
            }
        }
        return res;
    };
    map<pair<ll, ll>, int> mp;
    auto f = [&](auto f, mst x, mst y) -> void{
        ll b = x.SumTime - y.SumTime;
        ll a = y.SumMoney - x.SumMoney;
        mst z = get_mst(a, b);
        if(mp[{z.SumTime, z.SumMoney}]){
            return;
        }
        mp[{z.SumTime, z.SumMoney}] = 1;
        Convex_Hull.push_back(z);
        f(f, x, z);
        f(f, z, y);
    };
    Convex_Hull.push_back(get_mst(0, 1));
    Convex_Hull.push_back(get_mst(1, 0));
    f(f, Convex_Hull[0], Convex_Hull[1]);
    auto g = [&](mst x) -> ll{
        return x.SumTime*x.SumMoney;
    };
    mst best;
    best.SumTime = 1e9, best.SumMoney = 1e9;
    for(auto it : Convex_Hull){
        if(g(it) < g(best)){
            best = it;
        }
    }
    cout << best.SumTime << " " << best.SumMoney << "\n";
    for(auto it : best.e){
        cout << it.first << " " << it.second << "\n";
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    freopen("timeismoney.in", "r", stdin);
    freopen("timeismoney.out", "w", stdout);
    solve();
}

Compilation message (stderr)

timeismoney.cpp: In function 'int main()':
timeismoney.cpp:106:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |     freopen("timeismoney.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
timeismoney.cpp:107:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |     freopen("timeismoney.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100