Submission #225431

#	Time	Username	Problem	Language	Result	Execution time	Memory
225431		rqi	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	1429 ms	59820 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef double db; 
typedef string str; 

typedef pair<int,int> pi;
typedef pair<ll,ll> pl; 
typedef pair<db,db> pd; 

typedef vector<int> vi; 
typedef vector<ll> vl; 
typedef vector<db> vd; 
typedef vector<str> vs; 
typedef vector<pi> vpi;
typedef vector<pl> vpl; 
typedef vector<pd> vpd; 

#define mp make_pair 
#define f first
#define s second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#define lb lower_bound 
#define ub upper_bound 

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5; 
const ll INF = 1e18; 
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; 

template<class T> bool ckmin(T& a, const T& b) { 
    return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { 
    return a < b ? a = b, 1 : 0; } 
int pct(int x) { return __builtin_popcount(x); } 
int bit(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
int cdiv(int a, int b) { return a/b+!(a<0||a%b == 0); } // division of a by b rounded up, assumes b > 0 

// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);

template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }

template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
template<class A, class B> str ts(pair<A,B> p);
template<class A> str ts(complex<A> c) { return ts(mp(c.real(),c.imag())); }
str ts(bool b) { return b ? "true" : "false"; }
str ts(char c) { str s = ""; s += c; return s; }
str ts(str s) { return s; }
str ts(const char* s) { return (str)s; }
str ts(vector<bool> v) { 
    bool fst = 1; str res = "{";
    F0R(i,sz(v)) {
        if (!fst) res += ", ";
        fst = 0; res += ts(v[i]);
    }
    res += "}"; return res;
}
template<size_t SZ> str ts(bitset<SZ> b) {
    str res = ""; F0R(i,SZ) res += char('0'+b[i]);
    return res; }
template<class T> str ts(T v) {
    bool fst = 1; str res = "{";
    for (const auto& x: v) {
        if (!fst) res += ", ";
        fst = 0; res += ts(x);
    }
    res += "}"; return res;
}
template<class A, class B> str ts(pair<A,B> p) {
    return "("+ts(p.f)+", "+ts(p.s)+")"; }

// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
    pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
    pr(h); if (sizeof...(t)) pr(" "); ps(t...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << to_string(h); if (sizeof...(t)) cerr << ", ";
    DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 42
#endif

// FILE I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(string s = "") {
    unsyncIO();
    // cin.exceptions(cin.failbit); 
    // throws exception when do smth illegal
    // ex. try to read letter into int
    if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}

mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

const int mx = 100005;
ll sdist[mx];
ll tdist[mx];
vector<pair<int, ll>> adj[mx];
vi badj[mx];
vi cadj[mx];
ll fdist[5][mx];
int main() {
    setIO();
    int N, M;
    cin >> N >> M;
    int S, T;
    cin >> S >> T;
    int U, V;
    cin >> U >> V;
    for(int i = 1; i <= M; i++){
        int A, B;
        ll C;
        cin >> A >> B >> C;
        adj[A].pb(mp(B, C));
        adj[B].pb(mp(A, C));
    }
    for(int i = 1; i <= N; i++){
        tdist[i] = sdist[i] = INF;
    }
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> spq;
    spq.push(mp(0, S));
    while(sz(spq)){
        ll dist = spq.top().f;
        int node = spq.top().s;
        spq.pop();
        if(sdist[node] <= dist) continue;
        sdist[node] = dist;
        for(auto u: adj[node]){
            spq.push(mp(dist+u.s, u.f));
        }
    }
    spq.push(mp(0, T));
    while(sz(spq)){
        ll dist = spq.top().f;
        int node = spq.top().s;
        spq.pop();
        if(tdist[node] <= dist) continue;
        tdist[node] = dist;
        for(auto u: adj[node]){
            spq.push(mp(dist+u.s, u.f));
        }
    }

    for(int i = 1; i <= N; i++){
        for(auto u: adj[i]){
            if(sdist[T] == sdist[i]+u.s+tdist[u.f]){
                badj[i].pb(u.f);
                cadj[u.f].pb(i);
            }
        }
    }

    for(int j = 1; j <= 4; j++){
        for(int i = 1; i <= N; i++){
            fdist[j][i] = INF;
        }
    }
    priority_queue<pair<pair<int, ll>, int>, vector<pair<pair<int, ll>, int>>, greater<pair<pair<int, ll>, int>>> pq;
    pq.push(mp(mp(1, 0), U));
    while(sz(pq)){
        int typ = pq.top().f.f;
        ll dist = pq.top().f.s;
        int node = pq.top().s;
        pq.pop();
        if(fdist[typ][node] <= dist) continue;
        fdist[typ][node] = dist;
        if(typ == 1){
            for(auto u: adj[node]){
                pq.push(mp(mp(1, dist+u.s), u.f));
            }
            for(auto u: badj[node]){
                pq.push(mp(mp(2, dist), u));
            }
            for(auto u: cadj[node]){
                pq.push(mp(mp(3, dist), u));
            }
        }
        else if(typ == 2){
            for(auto u: badj[node]){
                pq.push(mp(mp(2, dist), u));
            }
            for(auto u: adj[node]){
                pq.push(mp(mp(4, dist+u.s), u.f));
            }
        }
        else if(typ == 3){
            for(auto u: cadj[node]){
                pq.push(mp(mp(3, dist), u));
            }
            for(auto u: adj[node]){
                pq.push(mp(mp(4, dist+u.s), u.f));
            }
        }
        else{
            for(auto u: adj[node]){
                pq.push(mp(mp(4, dist+u.s), u.f));
            }
        }
    }
    ll ans = INF;
    for(int j = 1; j <= 4; j++) ckmin(ans, fdist[j][V]);
    ps(ans);
    // you should actually read the stuff at the bottom
}

/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?)
    * do smth instead of nothing and stay organized
    * WRITE STUFF DOWN
*/

Compilation message (stderr)

commuter_pass.cpp: In function 'void setIn(std::__cxx11::string)':
commuter_pass.cpp:123:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp: In function 'void setOut(std::__cxx11::string)':
commuter_pass.cpp:124:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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