Submission #857243

#	Time	Username	Problem	Language	Result	Execution time	Memory
857243		quanlt206	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	245 ms	23880 KiB

commuter_pass

#include<bits/stdc++.h>
#define X first
#define Y second
#define all(x) begin(x), end(x)
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define FORD(i, b, a) for(int i = (b); i >= (a); i--)
#define REP(i, a, b) for (int i = (a); i < (b); i++)
#define mxx max_element
#define mnn min_element
#define SQR(x) (1LL * (x) * (x))
#define MASK(i) (1LL << (i))
#define Point Vector
#define left Left
#define right Right
#define div Div

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;
typedef pair<db, db> pdb;
typedef pair<ld, ld> pld;
typedef pair<int, int> pii;
typedef pair<int, pii> piii;
typedef pair<ll, ll> pll;
typedef pair<ll, pll> plll;
typedef pair<ll, int> pli;
typedef pair<ll, pii> plii;

template<class A, class B>
    bool maximize(A& x, B y) {
        if (x < y) return x = y, true; else return false;
    }
template<class A, class B>
    bool minimize(A& x, B y) {
        if (x > y) return x = y, true; else return false;
    }
/* END OF TEMPLATE */

const int N = 1e5 + 7;

vector<pii> v[N];

ll d[4][N];

int n, m, s, t, x, y;

void dijkstra(ll d[], int s) {
    FOR(i, 1, n) d[i] = 1e18;
    priority_queue<pli, vector<pli>, greater<pli>> pq;
    d[s] = 0;
    pq.push({d[s], s});
    while (!pq.empty()) {
        pli tmp = pq.top();
        pq.pop();
        ll w = tmp.X;
        int u = tmp.Y;
        if (w != d[u]) continue;
        for (auto x : v[u])
            if (minimize(d[x.X], w + x.Y)) pq.push({d[x.X], x.X});
    }
}

ll f[N], g[N];
int deg[N];
vector<int> adj[N];
bool onRoute[N];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin>>n>>m>>s>>t>>x>>y;
    FOR(i, 1, m) {
        int x, y, c;
        cin>>x>>y>>c;
        v[x].push_back({y, c});
        v[y].push_back({x, c});
    }
    dijkstra(d[0], s);
    dijkstra(d[1], t);
    dijkstra(d[2], x);
    dijkstra(d[3], y);
    FOR(i, 1, n)
        if (d[0][i] + d[1][i] == d[0][t]) onRoute[i] = true;
    FOR(x, 1, n)
        for (auto y : v[x])
            if (d[0][x] + y.Y == d[0][y.X]) {
                adj[x].push_back(y.X);
                deg[y.X]++;
            }
    ////  Topo
    vector<int> T;
    queue<int> qu;
    FOR(i, 1, n)
        if (deg[i] == 0) qu.push(i);
    while (!qu.empty()) {
        int x = qu.front();
        qu.pop();
        T.push_back(x);
        for (auto y : adj[x])
            if (--deg[y] == 0) qu.push(y);
    }
    reverse(all(T));
    for (auto x : T) {
        f[x] = g[x] = 1e18;
        if (onRoute[x]) f[x] = d[2][x], g[x] = d[3][x];
        for (auto y : adj[x]) {
            minimize(f[x], f[y]);
            minimize(g[x], g[y]);
        }
    }
    ll res = d[2][y];
    FOR(i, 1, n)
        if (onRoute[i]) {
            minimize(res, d[2][i] + g[i]);
            minimize(res, d[3][i] + f[i]);
        }
    cout<<res;
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45