Submission #1008967

#	Time	Username	Problem	Language	Result	Execution time	Memory
1008967		makanhulia	Commuter Pass (JOI18_commuter_pass)	C++17	16 / 100	158 ms	23752 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define pb push_back
#define pii pair<int, int>
#define all(x) x.begin(), x.end()
bool ckmin(int& a, int b){return b < a ? a = b, 1 : 0;}
bool ckmax(int& a, int b){return b > a ? a = b, 1 : 0;}
const int N = 2e5 + 5, mod = 1e9 + 7, INF = 1e18;
vector<pii> a[N];
int dp[N], dp2[N], dp3[N], val[N];
signed main(){
    ios_base::sync_with_stdio(0), cin.tie(0);
    int n, m, s, t, u, v; cin >> n >> m >> s >> t >> u >> v;
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    for(int i = 1; i <= m; i++) {
        int x, y, z; cin >> x >> y >> z;
        a[x].pb({y, z});
        a[y].pb({x, z});
    }
    for(int i = 1; i <= n; i++) dp[i] = dp3[i] = INF    ;
    pq.push({0, s});
    dp[s] = 0;
    while(!pq.empty()) {
        pii p = pq.top(); pq.pop();
        if(p.fi > dp[p.se]) continue;
        for(auto i : a[p.se]) {
            if(dp[i.fi] > p.fi + i.se) {
                dp[i.fi] = p.fi + i.se;
                pq.push({dp[i.fi], i.fi});
            }
        }
    }
    int mn = dp[t];
    queue<int> q;
    q.push(t);
    val[t] = 1;
    while(!q.empty()) {
        int p = q.front(); q.pop();
        for(auto i : a[p]) {
            if(dp[i.fi] + i.se == dp[p]) {
                if(!val[i.fi]) {
                    val[i.fi] = 1;
                    q.push(i.fi);
                }
            }
        }
    }
    pq.push({0, u}); 
    dp2[u] = 0;
    while(!pq.empty()) {
        pii p = pq.top(); pq.pop();
        if(p.fi > dp2[p.se]) continue;
        for(auto i : a[p.se]) {
            if(dp2[i.fi] > p.fi + i.se) {
                dp2[i.fi] = p.fi + i.se;
                pq.push({dp2[i.fi], i.fi});
            }
        }
    }
    pq.push({0, v});
    dp3[v] = 0;
    while(!pq.empty()) {
        pii p = pq.top(); pq.pop();
        if(p.fi > dp3[p.se]) continue;
        for(auto i : a[p.se]) {
            if(dp3[i.fi] > p.fi + i.se) {
                dp3[i.fi] = p.fi + i.se;
                pq.push({dp3[i.fi], i.fi});
            }
        }
    }
    int ans = INF;
    for(int i = 1; i <= n; i++) {
        if(val[i]) {
            ans = min(ans, dp3[i]);
        }
    }
    cout << ans << endl ;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:36:9: warning: unused variable 'mn' [-Wunused-variable]
   36 |     int mn = dp[t];
      |         ^~

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