Submission #1181994

#TimeUsernameProblemLanguageResultExecution timeMemory
1181994swishy123Commuter Pass (JOI18_commuter_pass)C++20
16 / 100
762 ms27184 KiB
#include <iostream>
#include <algorithm>
#include <vector>
#include <random>
#include <chrono>
#include <set>
#include <map>
#include <stack>
#include <functional>
#include <iomanip>
#include <queue>
#include <cassert>
#include <complex>
#include <cstring>
#include <memory>
#include <bitset>
#include <sstream>
#include <cmath>
#include <numeric>
#include <numbers>
#include <fstream>

using namespace std;

#ifndef template
#ifndef define
 
#define ll long long
#define ld long double
#define pl pair<ll, ll>
#define pi pair<int, int>
#define nl cout << '\n';
#define x first
#define y second 
#define cbit(x) __builtin_popcountll(x)
#define uid(a, b) uniform_int_distribution<ll>(a, b)(rng) 
#define siz(x) (int)x.size()
 
#endif
 
#ifndef print
void print(size_t x) {cout << x << ' ';}
void print(int x) {cout << x << ' ';}
void print(long long x) {cout << x << ' ';}
void print(float x) {cout << x << ' ';}
void print(long double x) {cout << x << ' ';}
void print(char x) {cout << x << ' ';}
void print(const char* x) {cout << x << ' ';}
void print(bool x) {cout << x << ' ';}
void print(string &x) {cout << x << ' ';}
 
template<typename T, typename V>
void print(pair<T, V> &p) {print(p.x); print(p.y);}
template<typename T>
void print(vector<T> v) {for (int i = 0; i < v.size(); i++) print(v[i]);}
template<typename T>
void print(vector<vector<T>> v) {
    for (int i = 0; i < v.size(); i++){
        for (int j = 0; j < v[i].size(); j++)
            print(v[i][j]);
        nl;
    }
}
template <typename T, typename... V>
void print(T t, V&&... v) {print(t); print(v...);}
 
#endif
 
#ifndef read
void read(int &x) {cin >> x;}
void read(long long &x) {cin >> x;}
void read(unsigned &x) {cin >> x;}
void read(unsigned long long &x) {cin >> x;}
void read(float &x) {cin >> x;}
void read(long double &x) {cin >> x;}
void read(char &x) {cin >> x;}
void read(string &x) {cin >> x;}
void read(bool &x) {cin >> x;}
 
template<typename T> 
void read(vector<T> &v) {
    for (int i = 0; i < v.size(); i++)
        read(v[i]);
}
template <typename T, typename... V>
void read(T &t, V&... v) {read(t); read(v...);}
#endif
 
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> bool maxi(T& a, const T& b) {
    return a < b ? a = b, 1 : 0;
}
template<class T> bool mini(T& a, const T& b) {
    return a > b ? a = b, 1 : 0;
}
template<class... Args>
auto vec(size_t n, Args&&... args) {
    if constexpr(sizeof...(args) == 1)
        return vector(n, args...);
    else
        return vector(n, vec(args...));
}

#endif

using namespace std;
const ll inf = 1e15;
const ll def = 2e5+1;
const ll mod = 998244353;

vector<ll> dijkstra(vector<vector<pi>> &edg, int s){
    int n = edg.size();
    priority_queue<pl, vector<pl>, greater<pl>> pq;

    auto dp = vec(n, inf);
    dp[s] = 0;

    pq.push({0, s});
    while (pq.size()){
        auto [dis, u] = pq.top();
        pq.pop();
        for (auto [v, w] : edg[u]){
            ll ndis = w + dis;
            if (ndis < dp[v]){
                dp[v] = ndis;
                pq.push({ndis, v});
            }
        }
    }
    return dp;
}

void solve(){ 
    int n, m;
    read(n, m);

    int s, t, U, V;
    read(s, t, U, V);

    s--; t--; U--; V--;
    vector<vector<pi>> edg(n);

    for (int i = 0; i < m; i++){
        int u, v, w;
        read(u, v, w);

        u--; v--;
        edg[u].push_back({v, w});
        edg[v].push_back({u, w});
    }
    auto dps = dijkstra(edg, s);
    auto dpt = dijkstra(edg, t);

    auto dp1 = vec(n, 3, inf);
    auto dp2 = dp1;
    priority_queue<pair<ll, pi>, vector<pair<ll, pi>>, greater<pair<ll, pi>>> pq;

    pq.push({0, {U, 0}});
    ll good = dps[t];

    dp1[U][0] = dp2[U][0] = 0;
    while (pq.size()){
        ll dis = pq.top().x;
        auto [u, has] = pq.top().y; pq.pop();
        
        for (auto [v, w] : edg[u]){
            for (int o = 0; o < 1; o++){
                ll ndis = dis;
                ll val = dps[u] + dpt[v] + w;
                ll nhas = has;
    
                if (o == 0 && val == good && has != 2){
                    if (!has)
                        nhas = 1;
                }
                else{
                    ndis += w;
                    if (nhas == 1)
                        nhas = 2;
                }
                if (ndis < dp1[v][nhas]){
                    dp1[v][nhas] = ndis;
                    pq.push({ndis, {v, nhas}});
                }
            }
        }
    }

    pq.push({0, {U, 0}});
    while (pq.size()){
        ll dis = pq.top().x;
        auto [u, has] = pq.top().y; pq.pop();
        
        for (auto [v, w] : edg[u]){
            for (int o = 0; o < 1; o++){
                ll ndis = dis;
                ll val = dps[u] + dpt[v] + w;
                ll nhas = has;
    
                if (o == 0 && val == good && has != 2){
                    if (!has)
                        nhas = 1;
                }
                else{
                    ndis += w;
                    if (nhas == 1)
                        nhas = 2;
                }
                if (ndis < dp2[v][nhas]){
                    dp2[v][nhas] = ndis;
                    pq.push({ndis, {v, nhas}});
                }
            }
        }
    }
    ll res = inf;
    for (int i = 0; i < 3; i++)
        mini(res, min(dp1[V][i], dp2[V][i]));
    print(res);
}         

/*
4 5
a s k A
d s D t
O R i A
a X b Y
b a k A -
u s k J

6
*/

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    if (ifstream("input.txt").good()){
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    }

    int t;
    t = 1;

    while (t--){
        solve();
        nl;
    }
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int32_t main()':
commuter_pass.cpp:239:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  239 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:240:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  240 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
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