제출 #757201

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
757201		sysia	Olympic Bus (JOI20_ho_t4)	C++17	37 / 100	1067 ms	3128 KiB

ho_t4

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

typedef pair<int, int> T;
set<T>cycle;
const long long oo = 1e18;
const int oo2 = 1e9+7;

vector<int> dijkstra(int n, vector<vector<T>>&g, int from, int to = -1){
    vector<int>dist(n+1, oo2);
    dist[from] = 0;
    set<T>s;
    vector<int>pre(n+1);
    s.insert({0, from});
    while ((int)s.size()){
        auto [d, v] = *s.begin();
        s.erase(s.begin());
        if (dist[v] < d) continue;
        for (auto [x, c]: g[v]){
            if (dist[x] > dist[v] + c){
                pre[x] = v;
                dist[x] = dist[v] + c;
                s.insert({dist[x], x});
            }
        }
    }
    if (to != -1){
        int now = to;
        vector<int>path;
        while (now){
            path.emplace_back(now);
            now = pre[now];
        }
        reverse(path.begin(), path.end());
        for (int i = 1; i<(int)path.size(); i++) cycle.insert({path[i-1], path[i]});
    }
    return dist;
}

int dijkstra2(int n, vector<vector<T>>&g, int from, int to = -1){
    vector<int>dist(n+1, oo2);
    dist[from] = 0;
    set<T>s;
    s.insert({0, from});
    while ((int)s.size()){
        auto [d, v] = *s.begin();
        s.erase(s.begin());
        if (dist[v] < d) continue;
        for (auto [x, c]: g[v]){
            if (dist[x] > dist[v] + c){
                dist[x] = dist[v] + c;
                s.insert({dist[x], x});
            }
        }
    }
    return dist[to];
}


void solve(){
    int n, m; cin >> n >> m;
    vector<vector<T>>g(n+1), gt(n+1);
    vector<tuple<int, int, int, int>>edges;
    for (int i = 0; i<m; i++){
        int a, b, c, d; cin >> a >> b >> c >> d;
        g[a].emplace_back(b, c);
        gt[b].emplace_back(a, c);
        edges.emplace_back(a, b, c, d);
    }
    auto d1 = dijkstra(n, g, 1, n); //1 do x
    auto dn = dijkstra(n, g, n, 1); //n do x
    auto d1rev = dijkstra(n, gt, 1); //x do 1
    auto dnrev = dijkstra(n, gt, n); //x do n
    long long ans = d1[n] + dn[1];
    int k = 0;
    debug(cycle);
    for (auto &[a, b, c, d]: edges){
        if (cycle.find({a, b}) != cycle.end()){
            debug(a, b);
            long long tmp = d;
            vector<vector<T>>G(n+1);
            for (int i = 0; i<m; i++){
                auto [A, B, C, D] = edges[i];
                if (i == k) {
                    G[B].emplace_back(A, C);
                    continue;
                }
                G[A].emplace_back(B, C);
            }
            tmp += dijkstra2(n, G, 1, n) + dijkstra2(n, G, n, 1);
            ans = min(ans, tmp);
        } else {
            ans = min(ans, (long long)d + (long long)min(d1[n], d1[b]+c+dnrev[a]) + (long long)min(dn[1], dn[b] + c + d1rev[a]));
        }
        k++;
    }
    if (ans >= oo2) cout << "-1\n";
    else cout << ans << "\n";
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 0 / 63