Submission #246029

#	Time	Username	Problem	Language	Result	Execution time	Memory
246029		WhaleVomit	Travelling Merchant (APIO17_merchant)	C++14	100 / 100	727 ms	22200 KiB

merchant

#include <bits/stdc++.h>
using namespace std;
 
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define sz(v) (int)v.size()
 
#define MOO(i, a, b) for(int i=a; i<b; i++)
#define M00(i, a) for(int i=0; i<a; i++)
#define MOOd(i,a,b) for(int i = (b)-1; i >= a; i--)
#define M00d(i,a) for(int i = (a)-1; i>=0; i--)
 
#define FAST ios::sync_with_stdio(0); cin.tie(0);
#define finish(x) return cout << x << '\n', 0;
#define dbg(x) cerr << ">>> " << #x << " = " << x << "\n";
#define _ << " _ " <<
 
template<class T> bool ckmin(T& a, const T& b) {return b < a ? a = b, 1 : 0;}
template<class T> bool ckmax(T& a, const T& b) {return a < b ? a = b, 1 : 0;}
 
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int,int> pi;
typedef pair<ld,ld> pd;
typedef complex<ld> cd;
 
template<int SZ> struct dijkstra {
    vector<pair<int, ll>> adj[SZ];
    bool vis[SZ];
    ll d[SZ];
 
    void addEdge(int u, int v, ll l) {
        adj[u].pb(mp(v, l));
    }
    ll dist(int v) {
        return d[v];
    }
    void build(int u) {
        M00(i, SZ) vis[i] = 0;
        M00(i, SZ) d[i] = 1e17;
        d[u] = 0;
        while(1) {
            pair<ll, int> t = mp(1e17, -1);
            M00(i, SZ) if(!vis[i]) ckmin(t, mp(d[i], i));
            if(t.s == -1 || vis[t.s]) return;
            vis[t.s] = 1;
 
            for(auto& v: adj[t.s]) if(!vis[v.f]) {
                ckmin(d[v.f], d[t.s] + v.s);
            }
        }
    }
};
 
const int MAX_N = 110;
const int MAX_K = 1010;
int n, m, k;
ll buy[MAX_N][MAX_K];
ll sell[MAX_N][MAX_K];
ll dist[MAX_N][MAX_N];
ll profit[MAX_N][MAX_N];
pair<ll,ll> dp[MAX_N][MAX_N][MAX_N]; // dp[u][v][s] : max efficiency u -> v, using s steps
dijkstra<MAX_N> dijk;
 
bool better(pair<ll,ll> p1, pair<ll,ll> p2) { // is p1 better efficiency?
    // p1.f / p1.s > p2.f / p2.s
    ld p1f = p1.f; ld p1s = p1.s;
    ld p2f = p2.f; ld p2s = p2.s;
    return p1f/p1s > p2f/p2s;
}
 
pair<ll,ll> sum(pair<ll,ll> p1, pair<ll,ll> p2) {
    return mp(p1.f + p2.f, p1.s + p2.s);
}
 
int main() { FAST
    cin >> n >> m >> k;
    M00(i, n) M00(j, k) cin >> buy[i][j] >> sell[i][j];
    M00(i, m) {
        int u, v; ll d;
        cin >> u >> v >> d;
        u--; v--;
        dijk.addEdge(u, v, d);
    }
    M00(i, n) {
        dijk.build(i);
        M00(j, n) {
            dist[i][j] = dijk.dist(j);
            ll val = 0;
            M00(ii, k) if(buy[i][ii] != -1 && sell[j][ii] != -1) ckmax(val, -buy[i][ii]+sell[j][ii]);
            if(i != j) profit[i][j] = val;
        }
    }
    M00(i, n) {
        M00(a, n) M00(b, n) dp[i][a][b] = mp(-1e17, 1);
        dp[i][i][0] = mp(0, 0);
        MOO(s, 1, n) {
            M00(j, n) {
                M00(p, n) if(p != j && dp[i][p][s-1].f != -1e17 && dist[p][j] != 1e17) {
                    pair<ll,ll> cand = sum(dp[i][p][s-1], mp(profit[p][j], dist[p][j]));
                    if(better(cand, dp[i][j][s])) dp[i][j][s] = cand;
                }
            }
        }
    }
    pair<ll,ll> res = mp(-1e17, 1);
    M00(i, n) {
        M00(j, n) if(j != i && dist[j][i] != 1e17) {
            M00(s, n) if(dp[i][j][s].f != -1e17) {
                pair<ll,ll> cand = sum(dp[i][j][s], mp(profit[j][i], dist[j][i]));
                if(better(cand, res)) {
                    res = cand;
                }
            }
        }
    }
    cout << max(0LL,res.f/res.s) << "\n";
}

• Subtask 1: 12 / 12
• Subtask 2: 21 / 21
• Subtask 3: 33 / 33
• Subtask 4: 34 / 34