Submission #1009787

#	Time	Username	Problem	Language	Result	Execution time	Memory
1009787		devariaota	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	1067 ms	90032 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()
#define ar array<int, 3>
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<ar> a[N];
vector<int> e[N];
int dp[N], dp2[N][3], dp3[N], val[N], vis[N], dp4[N][3];
map<pii, int> mp, mp2;
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, i});
        a[y].pb({x, z, i});
    }
    for(int i = 1; i <= n; i++) dp[i] = dp3[i] = INF;
    for(int i = 1; i <= n; i++) for(int j = 0; j < 3; j++) dp2[i][j] = dp4[i][j] = 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[0]] > p.fi + i[1]) {
                dp[i[0]] = p.fi + i[1];
                pq.push({dp[i[0]], i[0]});
            }
        }
    }
    int mn = dp[t];
    queue<int> q;
    q.push(t);
    while(!q.empty()) {
        int p = q.front(); q.pop();
        for(auto i : a[p]) {
            if(dp[i[0]] + i[1] == dp[p]) {
                if(!val[i[2]]) {
                    mp[{i[0], p}] = 1;
                    mp2[{p, i[0]}] = 1;
                    val[i[2]] = 1;
                    q.push(i[0]);
                }
            }
        }
    }
    priority_queue<ar, vector<ar>, greater<ar>> pqq;
    pqq.push({0, u, 0});
    dp2[u][0] = 0;
    while(!pqq.empty()) {
        ar p = pqq.top(); pqq.pop();
        if(p[0] > dp2[p[1]][p[2]]) continue;
        for(auto i : a[p[1]]) {
            if(!p[2] && mp[{p[1], i[0]}] && dp2[i[0]][1] > p[0]) {
                dp2[i[0]][1] = p[0];
                pqq.push({dp2[i[0]][1], i[0], 1});
            }
            if(!p[2] && dp2[i[0]][0] > p[0] + i[1]) {
                dp2[i[0]][0] = p[0] + i[1];
                pqq.push({dp2[i[0]][0], i[0], 0});
            }
            if(p[2] == 1 && mp[{p[1], i[0]}] && dp2[i[0]][1] > p[0]) {
                dp2[i[0]][1] = p[0];
                pqq.push({p[0], i[0], 1}); 
            } 
            if(p[2] == 1 && !mp[{p[1], i[0]}] && dp2[i[0]][2] > p[0] + i[1]) {
                dp2[i[0]][2] = p[0] + i[1];
                pqq.push({dp2[i[0]][2], i[0], 2});
            }
            if(p[2] == 2 && dp2[i[0]][2] > p[0] + i[1]) {
                dp2[i[0]][2] = p[0] + i[1];
                pqq.push({dp2[i[0]][2], i[0], 2});
            }
        }    
    }
    pqq.push({0, u, 0});
    dp4[u][0] = 0;
    while(!pqq.empty()) {
        ar p = pqq.top(); pqq.pop();
        if(p[0] > dp4[p[1]][p[2]]) continue;
        for(auto i : a[p[1]]) {
            if(!p[2] && mp2[{p[1], i[0]}] && dp4[i[0]][1] > p[0]) {
                dp4[i[0]][1] = p[0];
                pqq.push({dp4[i[0]][1], i[0], 1});
            }
            if(!p[2] && dp4[i[0]][0] > p[0] + i[1]) {
                dp4[i[0]][0] = p[0] + i[1];
                pqq.push({dp4[i[0]][0], i[0], 0});
            }
            if(p[2] == 1 && mp2[{p[1], i[0]}] && dp4[i[0]][1] > p[0]) {
                dp4[i[0]][1] = p[0];
                pqq.push({p[0], i[0], 1}); 
            } 
            if(p[2] == 1 && !mp2[{p[1], i[0]}] && dp4[i[0]][2] > p[0] + i[1]) {
                dp4[i[0]][2] = p[0] + i[1];
                pqq.push({dp4[i[0]][2], i[0], 2});
            }
            if(p[2] == 2 && dp4[i[0]][2] > p[0] + i[1]) {
                dp4[i[0]][2] = p[0] + i[1];
                pqq.push({dp4[i[0]][2], i[0], 2});
            }
        }    
    }
    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[0]] > p.fi + i[1]) {
                dp3[i[0]] = p.fi + i[1];
                pq.push({dp3[i[0]], i[0]});
            }
        }
    }
    int ans = INF;
    for(int i = 1; i <= n; i++) {
        int lol = INF;
        for(int j = 0; j < 3; j++) lol = min(lol, min(dp2[i][j], dp4[i][j]));
        ans = min(ans, dp3[i] + lol);
 
    }
    cout << ans << endl ;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:40:9: warning: unused variable 'mn' [-Wunused-variable]
   40 |     int mn = dp[t];
      |         ^~

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