Submission #944152

#	Time	Username	Problem	Language	Result	Execution time	Memory
944152		dwuy	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	291 ms	30032 KiB

commuter_pass

#include <bits/stdc++.h>

#define fastIO ios_base::sync_with_stdio(false); cin.tie(NULL)
#define file(a) freopen(a".inp","r",stdin); freopen(a".out", "w",stdout)
#define fi first
#define se second
#define endl "\n"
#define len(s) int32_t(s.length())
#define MASK(k)(1LL<<(k))
#define TASK "test"
#define int long long

using namespace std;

typedef tuple<int, int, int> tpiii;
typedef pair<double, double> pdd;
typedef pair<int, int> pii;
typedef long long ll;

const long long OO = 1e18;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const int MX = 200005;

int n, m;
int S, T, U, V;
vector<pii> G[MX];

void nhap(){
    cin >> n >> m;
    cin >> S >> T >> U >> V;
    for(int i=1; i<=m; i++){
        int u, v, c;
        cin >> u >> v >> c;
        G[u].push_back({v, c});
        G[v].push_back({u, c});
    }
}

void dijkstra(int u, int *d){
    for(int i=1; i<=n; i++) d[i] = 1e18;
    priority_queue<pii> Q;
    Q.push({0, u});
    d[u] = 0;
    while(Q.size()){
        int du, u;
        tie(du, u) = Q.top();
        du = -du;
        Q.pop();
        if(du != d[u]) continue;
        for(pii &tmp: G[u]){
            int v, c; tie(v, c) = tmp;
            c += du;
            if(c < d[v]){
                d[v] = c;
                Q.push({-c, v});
            }
        }
    }
}

int dS[MX];
int dT[MX];
int dU[MX];
int dV[MX];
int f[MX];
void solve(){
    dijkstra(S, dS);
    dijkstra(T, dT);
    dijkstra(U, dU);
    dijkstra(V, dV);
    int ans = dU[V];

    {
        memset(f, 0x3f, sizeof f);
        bitset<MX> vist = 0;
        vector<int> vt(n);
        for(int i=1; i<=n; i++) vt[i-1] = i;
        function<bool(const int &, const int &)> comp = [&](const int &a, const int &b){
            return dS[a] < dS[b];
        };
        sort(vt.begin(), vt.end(), comp);
        for(int u: vt) if(dS[u] + dT[u] == dS[T]){
            f[u] = dU[u]; 
            for(pii tmp: G[u]){
                int v, c; tie(v, c) = tmp;
                if(dS[v] + c == dS[u]) f[u] = min(f[u], f[v]);
            }   
            ans = min(ans, f[u] + dV[u]);
        }
    }
    {
        memset(f, 0x3f, sizeof f);
        bitset<MX> vist = 0;
        vector<int> vt(n);
        for(int i=1; i<=n; i++) vt[i-1] = i;
        function<bool(const int &, const int &)> comp = [&](const int &a, const int &b){
            return dS[a] < dS[b];
        };
        sort(vt.begin(), vt.end(), comp);
        for(int u: vt) if(dS[u] + dT[u] == dS[T]){
            f[u] = dV[u]; 
            for(pii tmp: G[u]){
                int v, c; tie(v, c) = tmp;
                if(dS[v] + c == dS[u]) f[u] = min(f[u], f[v]);
            }   
            ans = min(ans, f[u] + dU[u]);
        }
    }
    cout << ans;
}

int32_t main(){
    fastIO;
    //file(TASK);

    nhap();
    solve();

    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:76:20: warning: variable 'vist' set but not used [-Wunused-but-set-variable]
   76 |         bitset<MX> vist = 0;
      |                    ^~~~
commuter_pass.cpp:94:20: warning: variable 'vist' set but not used [-Wunused-but-set-variable]
   94 |         bitset<MX> vist = 0;
      |                    ^~~~

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