Submission #1108147

#	Time	Username	Problem	Language	Result	Execution time	Memory
1108147		chaoslong	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	249 ms	30472 KiB

commuter_pass

// Calm down.
// Think three times, code twice.
#include "bits/stdc++.h"
#define forr(_a,_b,_c) for(int _a = (_b); _a <= (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < (_c); ++_a)
#define st first
#define nd second
#define ll long long
#define ull unsigned long long
#define pii pair <ll,int>
#define pll pair <ll,ll>
#define piii pair <ll,pii>
#define vi vector <int>
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"

using namespace std;
const int N = 2e5 + 5;
const int mod = 1e9 + 7; // 998244353
const ll oo = 1e18;

ll ans;
int n, m, s, t, u, v;
vector<pii> a[N];
ll du[N], dv[N];

void xuly(int bd, ll d[]) {
    priority_queue<pii, vector<pii>, greater<pii>> q;
    q.push({0, bd}); d[bd] = 0;
    while(q.size()) {
        int u = q.top().nd; ll du = q.top().st; q.pop();
        if(du < d[u]) continue;
        for(pii e: a[u]) {
            int v = e.nd; ll dv = e.st;
            if(du + dv < d[v]) {
                d[v] = du + dv;
                q.push({d[v], v});
            }
        }
    }
}

void xuly2(int bd, int kt) {
    vector<ll> d(n + 5, oo);
    vector<vector<ll>> dp(2, vector<ll>(n+5, oo));
    priority_queue<piii, vector<piii>, greater<piii>> q;
    q.push({0, {bd, 0}}); d[bd] = 0;
    dp[0][bd] = du[bd]; dp[1][bd] = dv[bd];
    while(q.size()) {
        int u = q.top().nd.st, par = q.top().nd.nd; ll dist = q.top().st; q.pop();
        if(d[u] < dist) continue;
        for(pii e: a[u]) {
            int v = e.nd; ll distv = e.st;
            if(dist + distv < d[v]) {
                d[v] = dist + distv;
                dp[0][v] = min(dp[0][u], du[v]);
                dp[1][v] = min(dp[1][u], dv[v]);
                q.push({d[v], {v, u}});
            } else if(dist + distv == d[v]) {
                if(min(dp[0][u], du[v]) + min(dp[1][u], dv[v]) <= dp[0][v] + dp[1][v]) {
                    dp[0][v] = min(dp[0][u], du[v]);
                    dp[1][v] = min(dp[1][u], dv[v]);
                }
            }
        }
    }
//    cout << dp[0][kt] << " " << dp[1][kt] << "\n";
    ans = min(ans, dp[0][kt] + dp[1][kt]);
}

void to_nho_cau() {
    cin >> n >> m >> s >> t >> u >> v;
    forr(i, 1, m) {
        int u, v; ll val; cin >> u >> v >> val;
        a[u].pb({val, v});
        a[v].pb({val, u});
    }
    memset(du, 63, sizeof du);
    memset(dv, 63, sizeof dv);
    xuly(u, du); xuly(v, dv);
    ans = du[v];
    xuly2(s, t); xuly2(t, s);
    cout << ans << "\n";
}

signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    #ifdef LOCAL
        freopen(file".inp","r",stdin);
        freopen(file".out","w",stdout);
    #endif
    int t = 1;
    //cin >> t;
    while(t--) to_nho_cau();
}
/*
1.self check:
2.long long
3.size of array
4.code for testing
5.initializing
6.modulo number
*/
/**
  ∧__∧
（｀•ω• )づ__∧
（つ　 /( •ω•。)
  しーＪ (nnノ) pat pat
**/
/**  /\_/\
*   (= ._.)
*   / >☕ \>💻
**/

Compilation message (stderr)

commuter_pass.cpp:116:9: warning: "/*" within comment [-Wcomment]
  116 | /**  /\_/\
      |          
commuter_pass.cpp: In function 'void xuly2(int, int)':
commuter_pass.cpp:56:32: warning: unused variable 'par' [-Wunused-variable]
   56 |         int u = q.top().nd.st, par = q.top().nd.nd; ll dist = q.top().st; q.pop();
      |                                ^~~

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