Submission #546787

#	Time	Username	Problem	Language	Result	Execution time	Memory
546787		erto	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	570 ms	30420 KiB

commuter_pass

#include <bits/stdc++.h>
typedef long long int ll;
#define INF ll(1e18 + 7)
#define N (ll)1e5 + 5
using namespace std;
#define int ll

int n, m, s, t, u2, v, g, h, z, g2, h2, ans;
vector<pair<int, int>> v2[N];
bool used[N];
int ds[N], du[N], dv[N];
pair<int, int> d1[N], d2[N];

void bfs(){
    memset(used, 0, sizeof(used));
    priority_queue<pair<int, int>> q;
    q.push({0, s});
    pair<int, int> p;
    while(!q.empty()){
        p = q.top();
        q.pop();
        if(used[p.second])continue;
        used[p.second] = 1;
        for(auto u : v2[p.second]){
            if(!used[u.first] && ds[u.first] > ds[p.second] + u.second){
                ds[u.first] = ds[p.second] + u.second;
                q.push({-ds[u.first], u.first});
            }
        }
    }
}

void bfs2(){
    memset(used, 0, sizeof(used));
    priority_queue<pair<int, int>> q;
    q.push({0, u2});
    pair<int, int> p;
    while(!q.empty()){
        p = q.top();
        q.pop();
        if(used[p.second])continue;
        used[p.second] = 1;
        for(auto u : v2[p.second]){
            if(!used[u.first] && du[u.first] > du[p.second] + u.second){
                du[u.first] = du[p.second] + u.second;
                q.push({-du[u.first], u.first});
            }
        }
    }
}

void bfs3(){
    memset(used, 0, sizeof(used));
    priority_queue<pair<int, int>> q;
    q.push({0, v});
    pair<int, int> p;
    while(!q.empty()){
        p = q.top();
        q.pop();
        if(used[p.second])continue;
        used[p.second] = 1;
        for(auto u : v2[p.second]){
            if(!used[u.first] && dv[u.first] > dv[p.second] + u.second){
                dv[u.first] = dv[p.second] + u.second;
                q.push({-dv[u.first], u.first});
            }
        }
    }
}
bool visited[N];
int dp[2][N];

void dijkstra2(ll start, ll end) {
	fill(dp[0], dp[0] + 100001, LLONG_MAX / 2);
	fill(dp[1], dp[1] + 100001, LLONG_MAX / 2);
	fill(visited, visited + 100001, false);

	priority_queue<pair<ll, pair<ll, ll>>> pq;
	pq.push({0, {start, 0}});
	dp[0][0] = dp[1][0] = LLONG_MAX/ 2;
	while (!pq.empty()) {
		ll c, node, par;
		pair<ll, ll> p;
		tie(c, p) = pq.top();
		tie(node, par) = p;
		pq.pop();

		if (!visited[node]) {
			visited[node] = true;
			ds[node] = -c;
			dp[0][node] = min(du[node], dp[0][par]);
			dp[1][node] = min(dv[node], dp[1][par]);
			for (auto i : v2[node]) pq.push({c - i.second, {i.first, node}});
		} else if (-c == ds[node]) {
			if (min(du[node], dp[0][par]) + min(dv[node], dp[1][par]) <= dp[0][node] + dp[1][node]) {
				dp[0][node] = min(du[node], dp[0][par]);
				dp[1][node] = min(dv[node], dp[1][par]);
			}
		}
	}

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

void solve(){
    cin >> n >> m >> s >> t >> u2 >> v;
    for(int i=0; i<m; i++){
        cin >> g >> h >> z;
        v2[g].push_back({h, z});
        v2[h].push_back({g, z});
    }
    fill(ds, ds+n+1, INF);
    fill(du, du+n+1, INF);
    fill(dv, dv+n+1, INF);
    fill(d1, d1 + n + 1, make_pair(INF, INF));
    fill(d2, d2 + n + 1, make_pair(INF, INF));
    ds[s] = du[u2] = dv[v] = 0;
    bfs();
    bfs2();
    bfs3();

    ans = du[v];
    for(int i=1; i<=n; i++){
        d1[i] = d2[i] = {du[i], dv[i]};
    }
    int t1, t2, t3, t4;

    dijkstra2(s, t);
    dijkstra2(t, s);
    cout<<ans;

}
 
signed main(){
    //freopen("shortcut.in", "r", stdin);
    //freopen("shortcut.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int T = 1;
    //cin>>T;
    while (T--){
        solve();
    }
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:126:9: warning: unused variable 't1' [-Wunused-variable]
  126 |     int t1, t2, t3, t4;
      |         ^~
commuter_pass.cpp:126:13: warning: unused variable 't2' [-Wunused-variable]
  126 |     int t1, t2, t3, t4;
      |             ^~
commuter_pass.cpp:126:17: warning: unused variable 't3' [-Wunused-variable]
  126 |     int t1, t2, t3, t4;
      |                 ^~
commuter_pass.cpp:126:21: warning: unused variable 't4' [-Wunused-variable]
  126 |     int t1, t2, t3, t4;
      |                     ^~

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