Submission #851952

#	Time	Username	Problem	Language	Result	Execution time	Memory
851952		NK_	Senior Postmen (BOI14_postmen)	C++17	100 / 100	300 ms	105784 KiB

postmen

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
 
using namespace std;
 
#define nl '\n'
#define pb push_back
#define pf push_front
 
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
 
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
 
using db = long double;
 
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
 
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 18;

struct Scanner {
    FILE* stream;
    Scanner(FILE* s) : stream(s) {}
    char buf[1 << 20], * l = buf, * r = buf;
    bool flush() { l = buf; r = l + fread(buf, 1, 1 << 20, stream); return l == r; }
    void get(char& c) { c = l == r && flush() ? ' ' : *l++; }
    friend Scanner& operator >>(Scanner& in, char& c) { return in.get(c), in; }
    friend Scanner& operator >>(Scanner& in, char* s) {
        for (in.get(s[0]); isspace(s[0]); in.get(s[0]));
        for (int i = 0; !isspace(s[i]) || (s[i] = '\0'); i++) in.get(s[i + 1]);
        return in;
    }
    friend Scanner& operator >>(Scanner& in, std::string& s) {
        char c;
        for (in.get(c); isspace(c); in.get(c));
        for (s = ""; !isspace(c); in.get(c)) s += c;
        return in;
    }
    template <class T, std::enable_if_t<std::is_integral_v<T>, int> = 0>
    friend Scanner& operator >>(Scanner& in, T& x) {
        char c, f = '+';
        for (in.get(c); !isdigit(c); in.get(c))
            if constexpr (std::is_signed_v<T>) f = c;
        for (x = 0; isdigit(c); in.get(c)) x = x * (1 << 1) + x * (1 << 3) + c - '0';
        if constexpr (std::is_signed_v<T>) x = f == '-' ? -x : x;
        return in;
    }
    template <class T, std::enable_if_t<std::is_floating_point_v<T>, int> = 0>
    friend Scanner& operator >>(Scanner& in, T& x) {
        std::string s; in >> s; x = std::stod(s);
        return in;
    }
    template <class T, class U>
    friend Scanner& operator >>(Scanner& in, std::pair<T, U>& a) {
        return in >> a.first >> a.second;
    }
    template <class T, size_t S>
    friend Scanner& operator >>(Scanner& in, std::array<T, S>& a) {
        for (int i = 0, n = S; i < n; i++) in >> a[i];
        return in;
    }
    template <class T>
    friend Scanner& operator >>(Scanner& in, std::vector<T>& a) {
        for (int i = 0, n = a.size(); i < n; i++) in >> a[i];
        return in;
    }
};
 
struct Printer {
    FILE* stream;
    Printer(FILE* s) : stream(s) {}
    char buf[1 << 20], * l = buf, * r = buf + (1 << 20) - 1;
    int format = 0, precision = 15;
    ~Printer() { flush(); }
    void flush() { fwrite(buf, 1, l - buf, stream); l = buf; }
    void put(const char& c) { *l++ = c; if (l == r) flush(); }
    friend Printer& operator <<(Printer& out, const char& c) { return out.put(c), out; }
    friend Printer& operator <<(Printer& out, const char* s) {
        for (int i = 0; s[i] != '\0'; i++) out.put(s[i]);
        return out;
    }
    friend Printer& operator <<(Printer& out, const std::string& s) {
        for (int i = 0, n = s.size(); i < n; i++) out.put(s[i]);
        return out;
    }
    template <class T, std::enable_if_t<std::is_integral_v<T>, int> = 0>
    friend Printer& operator <<(Printer& out, T x) {
        static char s[40];
        static int i = 0;
        if (x == 0) { out.put('0'); return out; }
        if constexpr (std::is_signed_v<T>) x = x < 0 ? out.put('-'), -x : x;
        while (x > 0) s[++i] = x % 10 + '0', x /= 10;
        while (i > 0) out.put(s[i--]);
        return out;
    }
    template <class T, std::enable_if_t<std::is_floating_point_v<T>, int> = 0>
    friend Printer& operator <<(Printer& out, T x) {
        std::ostringstream oss;
        oss << std::fixed << std::setprecision(out.precision) << x;
        return out << oss.str();
    }
    template <class T, class U>
    friend Printer& operator <<(Printer& out, const std::pair<T, U>& a) {
        return out << a.first << " \n"[out.format > 1] << a.second;
    }
    template <class T, size_t S>
    friend Printer& operator <<(Printer& out, const std::array<T, S>& a) {
        out << a[0];
        for (int i = 1, n = S; i < n; i++) out << " \n"[out.format > 1] << a[i];
        return out;
    }
    template <class T>
    friend Printer& operator <<(Printer& out, const std::vector<T>& a) {
        if (!a.empty()) out << a[0];
        for (int i = 1, n = a.size(); i < n; i++) out << " \n"[out.format > 0] << a[i];
        return out;
    }
};

Scanner in(stdin);
Printer out(stdout);

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int N, M; in >> N >> M;

	V<vpi> adj(N); vi E(M);
	vi cur(N, 0);
	for(int i = 0; i < M; i++) {
		int u, v; in >> u >> v; --u, --v;
		adj[u].pb(mp(v, i));
		adj[v].pb(mp(u, i));
	}
	
	V<vi> ans;

	vi stk; vi vis(N); bool reset = 0;
	function<void(int)> dfs = [&](int u) {
		stk.pb(u); vis[u] = 1;
		// cerr << "ENTER " << u << endl;
		// cerr << "STK ";
		// for(auto& x : stk) cerr << x << " ";
		// cerr << endl;

		bool done = 1;
		while(cur[u] < sz(adj[u])) {
			int v, i; tie(v, i) = adj[u][cur[u]++];
			
			if (E[i]) continue;
			if (reset) return;
			done = 0; E[i] = 1;

			if (vis[v]) {
				vi cyc;
				for(int x = -1; x != v; ) {
					cyc.pb(x = stk.back()); stk.pop_back();
					vis[x] = 0;
				}
				// cerr << "CYC ";
				// for(auto& x : cyc) cerr << x << " ";
				// cerr << nl;


				ans.pb(cyc);
			}

			dfs(v); if (reset) return;
		}

		if (done) { 
			// cerr << "DONE " << u << endl;
			stk.pop_back(); vis[u] = -1; 
			reset = 1;
		}

		// cerr << "LEFT " << u << endl;
	};

	for(int i = 0; i < N; i++) {
		// cerr << i << " => " << vis[i] << endl;
		if (vis[i] != -1) dfs(i), reset = 0;
	}

	for(auto& v : ans) {
		for(auto& x : v) out << x + 1 << " ";
		out << nl;
	}

	exit(0-0);
} 

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 45 / 45