Submission #1181132

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181132		TudorMa	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	433 ms	23656 KiB

commuter_pass

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define fi first
#define sc second
#define pb push_back
#define int long long

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef double db;
typedef pair<int, int> pii;
template<typename type>
using ordered_set = tree<type, null_type, less<type>, rb_tree_tag, tree_order_statistics_node_update>;

const int N = 1e5 + 5, M = 2e5 + 5, mod = 1e9 + 7, inf = 1e18;
const int dl[] = {-1, 0, 1, 0}, dc[] = {0, 1, 0, -1};
const int ddl[] = {-1, -1, -1, 0, 1, 1, 1, 0}, ddc[] = {-1, 0, 1, 1, 1, 0, -1, -1};

mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
int rng(int lo = 1, int hi = INT_MAX) {
    uniform_int_distribution<int> rnd(lo, hi);
    return rnd(gen);
}

struct mint {
    int val;
    mint(int32_t x = 0) {
        val = x % mod;
    }
    mint(long long x) {
        val = x % mod;
    }
    mint operator+(mint x) {
        return val + x.val;
    }
    mint operator-(mint x) {
        return val - x.val + mod;
    }
    mint operator*(mint x) {
        return 1LL * val * x.val;
    }
    void operator+=(mint x) {
        val = (*this + x).val;
    }
    void operator-=(mint x) {
        val = (*this - x).val;
    }
    void operator*=(mint x) {
        val = (*this * x).val;
    }
    friend auto operator>>(istream& in, mint &x) -> istream& {
        in >> x.val;
        x.val %= mod;
        return in;
    }
    friend auto operator<<(ostream& out, mint const &x) -> ostream& {
        out << x.val;
        return out;
    }
};

int n, m, s, t, u, v, ans, w[M], dst[3][N], dp[2][N];
bool vzt[N], taken[M], onpath[N];
vector<pii> g[N];

void dijk(int start, int st) {
    for(int i=1; i<=n; i++)
        dst[st][i] = inf;
    dst[st][start] = 0;
    priority_queue<pii, vector<pii>, greater<pii>> que;
    que.push({0, start});
    while(!que.empty()) {
        auto [d, nod] = que.top();
        que.pop();
        if(d != dst[st][nod])
            continue;
        
        for(auto &[id, nxt] : g[nod])
            if(d + w[id] < dst[st][nxt]) {
                dst[st][nxt] = d + w[id];
                que.push({dst[st][nxt], nxt});
            }
    }
}
void ohio() {
    dijk(u, 1);
    dijk(v, 2);
    ans = min(ans, dst[1][v]);

    memset(vzt, 0, sizeof(vzt));
    for(int i=0; i<=n; i++)
        dst[0][i] = dp[0][i] = dp[1][i] = inf;
    dst[0][s] = 0;
    priority_queue<tuple<int, int, int>, vector<tuple<int, int, int>>, greater<tuple<int, int, int>>> que;
    que.push({0, s, 0});
    while(!que.empty()) {
        auto [d, nod, par] = que.top();
        que.pop();
        if(d != dst[0][nod])
            continue;
        
        if(min(dst[1][nod], dp[0][par]) + min(dst[2][nod], dp[1][par]) < dp[0][nod] + dp[1][nod]) {
            dp[0][nod] = min(dst[1][nod], dp[0][par]);
            dp[1][nod] = min(dst[2][nod], dp[1][par]);
        }
        if(!vzt[nod]) {
            vzt[nod] = 1;
            for(auto &[id, nxt] : g[nod])
                if(dst[0][nxt] >= d + w[id]) {
                    dst[0][nxt] = d + w[id];
                    que.push({dst[0][nxt], nxt, nod});
                }
        }
    }

    ans = min(ans, dp[0][t] + dp[1][t]);
}

int32_t main()
{
    cin.tie(nullptr)->sync_with_stdio(0);
    
    cin >> n >> m;
    cin >> s >> t;
    cin >> u >> v;
    for(int i=1; i<=m; i++) {
        int x, y;
        cin >> x >> y >> w[i];
        g[x].pb({i, y});
        g[y].pb({i, x});
    }

    ans = inf;
    ohio();
    swap(s, t);
    ohio();

    cout << ans;
    return 0;
}

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