Submission #336872

#	Time	Username	Problem	Language	Result	Execution time	Memory
336872		12tqian	Portals (BOI14_portals)	C++17	70 / 100	1020 ms	117484 KiB

portals

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
 
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <iomanip>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
 
using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
 
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<bool> vb;
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 sor(x) sort(all(x))
#define rsz resize
#define resz 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 f1r(i, a, b) for (int i = (a); i < (b); ++i)
#define f0r(i, a) f1r(i, 0, a)
#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)
 
mt19937 rng((uint32_t) chrono::steady_clock::now().time_since_epoch().count());
 
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; }
template<class T> using V = vector<T>;
 
#ifdef LOCAL
#define dbg(...) debug(#__VA_ARGS__, __VA_ARGS__);
#else
#define dbg(...) 17;
#endif
 
template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) { return os << "(" << p.first << ", " << p.second << ")"; }
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) { bool f = true; os << "{"; for (const auto &x : c) { if (!f) os << ", "; f = false; os << x; } return os << "}"; }
template<typename T> void debug(string s, T x) { cerr << s << " = " << x << "\n"; }
template<typename T, typename... Args> void debug(string s, T x, Args... args) { cerr << s.substr(0, s.find(',')) << " = " << x << " | "; debug(s.substr(s.find(',') + 2), args...); }
 
constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int bits(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))
 
namespace input {
    template<class T> void re(complex<T>& x);
    template<class T1, class T2> void re(pair<T1, T2>& p);
    template<class T> void re(vector<T>& a);
    template<class T, int SZ> void re(array<T, SZ>& a);
    template<class T> void re(T& x) { cin >> x; }
    void re(double& x) { string t; re(t); x = stod(t); }
    void re(ld& x) { string t; re(t); x = stold(t); }
    template<class T, class... Ts> void re(T& t, Ts&... ts) {
        re(t); re(ts...); }
    template<class T> void re(complex<T>& x) { T a, b; re(a, b); x = cd(a, b); }
    template<class T1, class T2> void re(pair<T1, T2>& p) { re(p.f, p.s); }
    template<class T> void re(vector<T>& a) { F0R(i, sz(a)) re(a[i]); }
    template<class T, int SZ> void re(array<T, SZ>& a) { F0R(i, SZ) re(a[i]); }
}
 
using namespace input;
 
namespace output {
    void pr(int x) { cout << x; }
    void pr(long x) { cout << x; }
    void pr(ll x) { cout << x; }
    void pr(unsigned x) { cout << x; }
    void pr(unsigned long x) { cout << x; }
    void pr(unsigned long long x) { cout << x; }
    void pr(float x) { cout << x; }
    void pr(double x) { cout << x; }
    void pr(ld x) { cout << x; }
    void pr(char x) { cout << x; }
    void pr(const char* x) { cout << x; }
    void pr(const string& x) { cout << x; }
    void pr(bool x) { pr(x ? "true" : "false"); }
    template<class T> void pr(const complex<T>& x) { cout << x; }
    template<class T1, class T2> void pr(const pair<T1, T2>& x);
    template<class T> void pr(const T& x);
    template<class T, class... Ts> void pr(const T& t, const Ts&... ts) {
        pr(t); pr(ts...); }
    template<class T1, class T2> void pr(const pair<T1,T2>& x) {
        pr("{", x.f, ", ", x.s, "}"); }
    template<class T> void pr(const T& x) {
        pr("{"); // const iterator needed for vector<bool>
        bool fst = 1; for (const auto& a: x) pr(!fst ? ", " : "", a), fst = 0;
        pr("}"); }
    void ps() { pr("\n"); } // print w/ spaces
    template<class T, class... Ts> void ps(const T& t, const Ts&... ts) {
        pr(t); if (sizeof...(ts)) pr(" "); ps(ts...); }
    void pc() { pr("]\n"); } // debug w/ commas
    template<class T, class... Ts> void pc(const T& t, const Ts&... ts) {
        pr(t); if (sizeof...(ts)) pr(", "); pc(ts...); }
}
 
using namespace output;
 
namespace io {
    void setIn(string s) { freopen(s.c_str(), "r", stdin); }
    void setOut(string s) { freopen(s.c_str(), "w", stdout); }
    void setIO(string s = "") {
        cin.sync_with_stdio(0); cin.tie(0);
        if (sz(s)) { setIn(s + ".in"), setOut(s + ".out"); }
    }
}
 
using namespace io;
 
const int MOD = 1e9 + 7; // 998244353;
const ld PI = acos((ld) -1);
 
typedef std::decay <decltype(MOD)>::type mod_t;
struct mi {
    mod_t val;
    explicit operator mod_t() const { return val; }
    mi() { val = 0; }
    mi(const long long& v) {
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD; }
    friend std::istream& operator >> (std::istream& in, mi& a) { 
        long long x; std::cin >> x; a = mi(x); return in; }
    friend std::ostream& operator << (std::ostream& os, const mi& a) { return os << a.val; }
    friend void pr(const mi& a) { pr(a.val); }
    friend void re(mi& a) { long long x; cin >> x; a = mi(x); }
    friend bool operator == (const mi& a, const mi& b) { return a.val == b.val; }
    friend bool operator != (const mi& a, const mi& b) { return !(a == b); }    
    friend bool operator < (const mi& a, const mi& b) { return a.val < b.val; }
    friend bool operator > (const mi& a, const mi& b) { return a.val > b.val; }
    friend bool operator <= (const mi& a, const mi& b) { return a.val <= b.val; }
    friend bool operator >= (const mi& a, const mi& b) { return a.val >= b.val; }
    mi operator - () const { return mi(-val); }
    mi& operator += (const mi& m) {
        if ((val += m.val) >= MOD) val -= MOD;
        return *this; }
    mi& operator -= (const mi& m) {
        if ((val -= m.val) < 0) val += MOD;
        return *this; }
    mi& operator *= (const mi& m) { val = (long long) val * m.val % MOD;
        return *this; }
    friend mi pow(mi a, long long p) {
        mi ans = 1; assert(p >= 0);
        for (; p; p /= 2, a *= a) if (p & 1) ans *= a;
        return ans; }
    friend mi inv(const mi& a) { assert(a != 0); return pow(a, MOD - 2); }
    mi& operator /= (const mi& m) { return (*this) *= inv(m); }
    friend mi operator + (mi a, const mi& b) { return a += b; }
    friend mi operator - (mi a, const mi& b) { return a -= b; }
    friend mi operator * (mi a, const mi& b) { return a *= b; }
    friend mi operator / (mi a, const mi& b) { return a /= b; }
};
typedef pair<mi, mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;
const int N = 1005;
const int M = N*N;
short dx[4] = {0, 0, 1, -1};
short dy[4] = {1, -1, 0, 0};
short vis[M];
short dist[M];
short g[N][N];
short close[N][N];
template <class C, bool directed> struct Dijkstra {
    int SZ; std::vector<C> dist;
    std::vector<std::vector<std::pair<int, C>>> adj;
    void init(int _SZ) {
        SZ = _SZ;
        adj.clear();
        adj.resize(SZ);
    }
    void ae(int u, int v, C cost) {
        adj[u].emplace_back(v, cost);
        if (!directed) adj[v].emplace_back(u, cost);
    }
    void gen(int st) {
        dist = std::vector<C>(SZ, std::numeric_limits<C>::max());
        typedef std::pair<C, int> T;
        std::priority_queue<T, std::vector<T>, std::greater<T>> pq;
        auto ad = [&](int a, C b) {
            if (dist[a] <= b) return;
            pq.push({dist[a] = b, a});
        };
        ad(st, 0);
        while (!pq.empty()) {
            auto x = pq.top();
            pq.pop();
            if (dist[x.second] < x.first) continue;
            for (auto& y: adj[x.second]) {
                ad(y.first, x.first + y.second);
            }
        }
    }
};
int main() {
    setIO("");
    int r, c; re(r, c);
    Dijkstra<short, true> D;
    D.init(r*c);
    pi st;
    pi ed;
    f0r(i, r) {
        string line; re(line);
        f0r(j, c) {
            if (line[j] == '#') g[i][j] = 1;
            if (line[j] == 'S') st = {i, j};
            if (line[j] == 'C') ed = {i, j};
        }
    }
    auto wall = [&](int i, int j) -> bool {
        if (i==0||j==0||i==r-1||j==c-1) return 1;
        f0r(d, 4) {
            int ni = i+dx[d];
            int nj = j+dy[d];
            if (g[ni][nj]) return 1;
        }
        return 0;
    };
    auto conv = [&](int a, int b) -> int {
        return a*c+b;
    };
    auto ae = [&](int w, int x, int y, int z, short we) {
        int u = conv(w, x);
        int v = conv(y, z);
        D.ae(u,v,we);
        D.ae(v,u,we);
    };
    auto ao = [&](int w, int x, int y, int z, short we) {
        int u = conv(w, x);
        int v = conv(y, z);
        D.ae(u,v,we);
    };
    list<int> que;
    f0r(i, r) {
        f0r(j, c) {
            if (wall(i,j)) {
                que.pb(conv(i,j));
                vis[conv(i,j)]=1;
            }
        }
    }
    while (!que.empty()) {
        int s = que.front();
        que.pop_front();
        f0r(d, 4) {
            int i = s/c;
            int j = s%c;
            int ni = i + dx[d];
            int nj = j + dy[d];
            if (ni<0||nj<0||ni>=r||nj>=c) continue;
            if (g[ni][nj]) continue;
            int nxt = ni*c+nj;
            if (vis[nxt]) continue;
            vis[nxt] = 1;
            close[ni][nj] = close[i][j]+1;
            que.pb(nxt);
        }
    }
    f0r(i, r) {
        // furthest to the left
        int cur = 0;
        f0r(j, c) {
            if (g[i][j]) {
                cur = j+1;
            } else {
                ao(i,j,i,cur,close[i][j]+1);
            }
        }
        cur = c-1;
        for (int j = c-1; j >= 0; j--) {
            if (g[i][j]) {
                cur = j-1;
            } else {
                ao(i,j,i,cur,close[i][j]+1);
            }
        }
    }
    f0r(j, c) {
        int cur = 0;
        f0r(i, r) {
            if (g[i][j]) {
                cur = i+1;
            } else {
                ao(i,j,cur,j,close[i][j]+1);
            }
        }
        cur = r-1;
        for (int i = r-1; i >= 0; i--) {
            if (g[i][j]) {
                cur = i-1;
            } else {
                ao(i,j,cur,j,close[i][j]+1);
            }
        }
    }
    f0r(i, r) {
        f0r(j, c-1) {
            if (g[i][j]||g[i][j+1]) continue;
            ae(i,j,i,j+1,1);
        }
    }
    f0r(j, c) {
        f0r(i, r-1) {
            if (g[i][j]||g[i+1][j]) continue;
            ae(i,j,i+1,j,1);
        }
    }
    D.gen(conv(st.f,st.s));
    cout << (D.dist[conv(ed.f,ed.s)]) << '\n';
    return 0;
}

Compilation message (stderr)

portals.cpp: In function 'void io::setIn(std::string)':
portals.cpp:153:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  153 |     void setIn(string s) { freopen(s.c_str(), "r", stdin); }
      |                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
portals.cpp: In function 'void io::setOut(std::string)':
portals.cpp:154:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  154 |     void setOut(string s) { freopen(s.c_str(), "w", stdout); }
      |                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 19 / 19
• Subtask 5: 0 / 30