Submission #999558

#	Time	Username	Problem	Language	Result	Execution time	Memory
999558		whatthemomooofun1729	Traffic (CEOI11_tra)	C++17	100 / 100	438 ms	101412 KiB

tra

#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <stack>
#include <map>
#include <queue>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cstring>
#include <cmath>
#include <functional>
#include <cassert>
#include <iomanip>
#include <numeric>
#include <bitset>
#include <sstream>
#include <chrono>
#include <random>

#define ff first
#define ss second
#define PB push_back
#define sz(x) int(x.size())
#define rsz resize
#define fch(xxx, yyy) for (auto xxx : yyy) // abusive notation
#define all(x) (x).begin(),(x).end()
#define eps 1e-9

// more abusive notation (use at your own risk):
//#define int ll

using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;

// debugging
void __print(int x) {std::cerr << x;}
void __print(ll x) {std::cerr << x;} /* remember to uncomment this when not using THE MACRO */
void __print(unsigned x) {std::cerr << x;}
void __print(ull x) {std::cerr << x;}
void __print(float x) {std::cerr << x;}
void __print(double x) {std::cerr << x;}
void __print(ld x) {std::cerr << x;}
void __print(char x) {std::cerr << '\'' << x << '\'';}
void __print(const char *x) {std::cerr << '\"' << x << '\"';}
void __print(const string& x) {std::cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V> void __print(const pair<T, V> &x) {std::cerr << '{'; __print(x.ff); std::cerr << ", "; __print(x.ss); std::cerr << '}';}
template<typename T> void __print(const T& x) {int f = 0; std::cerr << '{'; for (auto &i: x) std::cerr << (f++ ? ", " : ""), __print(i); std::cerr << "}";}
void _print() {std::cerr << "]\n";}
template <typename T, typename... V> void _print(T t, V... v) {__print(t); if (sizeof...(v)) std::cerr << ", "; _print(v...);}
void println() {std::cerr << ">--------------------<" << endl;}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

// templates
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 b>a ? a = b, 1 : 0;}
template <class T> using gr = greater<T>;
template <class T> using vc = vector<T>;
template <class T> using p_q = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vc<T>, gr<T>>;
template <class T1, class T2> using pr = pair<T1, T2>;
mt19937_64 rng_ll(chrono::steady_clock::now().time_since_epoch().count());
int rng(int M) {return (int)(rng_ll()%M);} /*returns any random number in [0, M) */

// const variables
constexpr int INF = (int)2e9;
constexpr int MOD = 998244353;
constexpr ll LL_INF = (ll)3e18;
constexpr int mod = (int)1e9 + 7;
constexpr ll inverse = 500000004LL; // inverse of 2 modulo 1e9 + 7

void setIO(const string& str) {// fast input/output
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (str.empty()) return;
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
}

struct SCC {
    /*
     * Author: William Wang
     * Date: 4/17/2024
     * Source: https://cp-algorithms.com/graph/strongly-connected-components.html
     * Status: Tested on USACO Gold Grass Cownoisseur
     * */
    int N, C;
    vc<vi> adj, adj_;
    vc<vi> adjc;
    vi vst, order, comp, cc;
    SCC() {}
    SCC(int n, vc<vi> jda) { // jda = O(M) space, passing by value is fine
        N = n;
        C = 0;
        adj = jda;
        vst.clear(), order.clear(), comp.clear(), cc.clear();
        vst.rsz(N+1, 0), comp.rsz(N+1), cc.rsz(N+1, -1);
        adj_.rsz(N+1);
        for (int i = 1; i <= N; ++i) { // change index bounds if needed
            while (!jda[i].empty()) {
                int u = jda[i].back();
                adj_[u].PB(i);
                jda[i].pop_back();
            }
        }
    }
    void dfs1(int v) {
        vst[v] = 1;
        for (int u : adj[v]) if (!vst[u]) dfs1(u);
        order.PB(v);
    }
    void dfs2(int v) {
        vst[v] = 1;
        comp.PB(v);
        for (int u : adj_[v]) if (!vst[u]) dfs2(u);
    }
    void condense() {
        vst.clear(), vst.rsz(N+1, 0), adjc.clear(), adjc.rsz(N+1);
        for (int i = 1; i <= N; ++i) if (!vst[i]) dfs1(i);
        vst.clear(), vst.rsz(N+1, 0);
        reverse(all(order));
        C = 0;
        for (int v : order) {
            if (!vst[v]) {
                dfs2(v);
                for (int u : comp) {
                    cc[u] = C;
                }
                comp.clear();
                C++;
            }
        }
        for (int i = 1; i <= N; ++i) {
            for (int u : adj[i]) {
                if (cc[u] != cc[i]) adjc[cc[i]].PB(cc[u]); // reminder: contains duplicates
            }
        }
    }
};

int N, M, A, B, C;
vc<pii> west, east;
vi rem, lo, hi, order, visited;
SCC scc;
vc<vi> adj, adj_;

void bfs() {
    queue<int> q;
    vi vst(N+1, 0);
    for (int i = 0; i < sz(west); ++i) {
        vst[west[i].ss] = 1;
        q.push(west[i].ss);
    }
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        fch(u, adj[v]) if (!vst[u]) {
            vst[u] = 1;
            q.push(u);
        }
    }
    for (int i = 0; i < sz(east); ++i) {
        rem[i] = !vst[east[i].ss];
    }
}

void dfs(int v) {
    visited[v] = 1;
    fch(u, adj_[v]) if (!visited[u]) {
        dfs(u);
    }
    order.PB(v);
}

signed main() { // TIME YOURSELF !!!
    setIO("");
    cin >> N >> M >> A >> B;
    adj.rsz(N+1);
    for (int i = 1; i <= N; ++i) {
        int x, y;
        cin >> x >> y;
        if (x == 0) {
            west.PB({y, i});
        } else if (x == A) {
            east.PB({y, i});
        }
    }
    rem.rsz(sz(east));
    for (int i = 0; i < M; ++i) {
        int c, d, k;
        cin >> c >> d >> k;
        adj[c].PB(d);
        if (k == 2) {
            adj[d].PB(c);
        }
    }
    sort(all(west)), sort(all(east));
    bfs();
    scc = SCC(N, adj);
    scc.condense();
    C = scc.C, adj_ = scc.adjc;
    lo.rsz(C, INF), hi.rsz(C, -1), visited.rsz(C, 0);
//    for (int i = 1; i <= N; ++i) {
//        debug(i, scc.cc[i]);
//    }
    for (int i = 0; i < sz(east); ++i) {
        if (rem[i]) continue;
        int v = east[i].ss;
        ckmin(lo[scc.cc[v]], i);
        ckmax(hi[scc.cc[v]], i);
    }
    for (int i = 0; i < C; ++i) {
        if (!visited[i]) {
            dfs(i);
        }
    }
    for (int i = 0; i < sz(order); ++i) {
        int c = order[i];
        fch(u, adj_[c]) {
            ckmin(lo[c], lo[u]);
            ckmax(hi[c], hi[u]);
        }
    }
    for (int i = 0; i < sz(east); ++i) {
        rem[i] = (i > 0 ? rem[i-1] : 0) + rem[i];
    }
    for (int i = sz(west)-1; i >= 0; --i) {
        int v = west[i].ss;
        int l = lo[scc.cc[v]], h = hi[scc.cc[v]];
        if (l > h) {
            cout << "0\n";
            continue;
        }
        cout << h - l + 1 - (rem[h] - (l > 0 ? rem[l - 1] : 0)) << '\n';
    }
    return 0;
}

// TLE -> TRY NOT USING DEFINE INT LONG LONG
// CE -> CHECK LINE 45
// 5000 * 5000 size matrices are kinda big (potential mle)
// Do something, start simpler

Compilation message (stderr)

tra.cpp: In function 'void setIO(const string&)':
tra.cpp:88:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tra.cpp:89:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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