Submission #937042

#	Time	Username	Problem	Language	Result	Execution time	Memory
937042		Whisper	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	268 ms	26716 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define Lg(x) 31 - __builtin_clz(x)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)

constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 1e5 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void setupIO(){
    #define name "Whisper"
    //Phu Trong from Nguyen Tat Thanh High School for gifted student
    srand(time(NULL));
    cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    cout << fixed << setprecision(10);
}

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
int numNode, numEdge;

vector<pair<int, int>> adj[MAX];

int F[MAX][4], node[4];
void dijkstra(int x){
    for (int i = 1; i <= numNode; ++i) F[i][x] = LINF;
    F[node[x]][x] = 0;

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
    q.emplace(0, node[x]);
    while (q.size()){
        pair<int, int> f = q.top(); q.pop();
        int du = f.first, u = f.second;
        if (F[u][x] < du) continue;
        for (pair<int, int> &c : adj[u]){
            int v = c.first, w = c.second;
            if (minimize(F[v][x], F[u][x] + w)){
                q.emplace(F[v][x], v);
            }
        }
    }
}

vector<int> G[MAX];

int dpU[MAX], dpV[MAX];
int vis[MAX];
int res;
void dp(int u){
    if (vis[u]) return;
    vis[u] = 1;
    for (int &v : G[u]){
        minimize(dpU[v], dpU[u]);
        minimize(dpU[v], F[v][2]);

        minimize(dpV[v], dpV[u]);
        minimize(dpV[v], F[v][3]);
        dp(v);
    }
    if (u)
        minimize(res, dpU[u] + F[u][3]);
        minimize(res, dpV[u] + F[u][2]);
}
void Whisper(){
    cin >> numNode >> numEdge;
    REP(i, 4) cin >> node[i];
    for (int i = 1; i <= numEdge; ++i){
        int u, v, w; cin >> u >> v >> w;
        adj[u].emplace_back(v, w);
        adj[v].emplace_back(u, w);
    }

    REP(i, 4) dijkstra(i);
    G[0].push_back(node[0]);
    for (int u = 1; u <= numNode; ++u){
        for (pair<int, int>& x : adj[u]){
            int v = x.first, w = x.second;
            if (F[u][0] + w + F[v][1] == F[node[1]][0]){
                G[u].push_back(v);
            }
        }
    }
    for (int i = 0; i <= numNode; ++i) dpU[i] = dpV[i] = LINF;
    res = F[node[2]][3];

    dp(0);
    cout << res;
}


signed main(){
    setupIO();
    int Test = 1;
//    cin >> Test;
    for ( int i = 1 ; i <= Test ; i++ ){
        Whisper();
        if (i < Test) cout << '\n';
    }
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void dp(long long int)':
commuter_pass.cpp:85:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   85 |     if (u)
      |     ^~
commuter_pass.cpp:87:9: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   87 |         minimize(res, dpV[u] + F[u][2]);
      |         ^~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45