제출 #409050

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
409050		Kevin_Zhang_TW	From Hacks to Snitches (BOI21_watchmen)	C++17	35 / 100	1880 ms	98924 KiB

watchmen

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
void debug(auto l, auto r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

using t3 = pair<ll,int>;
const int MAX_N = 300010, MAX_K = 2800, hol = 100;
const ll inf = 1ll << 55;

int n, m;
vector<int> edge[MAX_N], cyc[MAX_N];

ll dp[MAX_N][2];

int cid[MAX_N], csz[MAX_N], cpos[MAX_N];

int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	// init everything
	cin >> n >> m;
	for (int a, b, i = 0;i < m;++i) {
		cin >> a >> b;
		edge[a].pb(b);
		edge[b].pb(a);
	}
	for (int i = 1;i <= n;++i) {
		dp[i][0] = dp[i][1] = inf;
		csz[i] = 1;
	}
	int K;
	cin >> K;
	for (int i = 1;i <= K;++i) {
		int len;
		cin >> len;
		cyc[i].resize(len);
		int c = 0;
		for (int &u : cyc[i]) {
			cin >> u;
			cid[u] = i;
			csz[u] = len;
			cpos[u] = c++;
		}
	}

	//priority_queue<t3, vector<t3>, greater<t3>> q;
	//queue<pair<ll,int>> q;

	vector<vector<int>> q;
	auto putin = [&](int d, int x) {
		if (q.size() < d + 1) q.resize(d + 1);
		q[d].pb(x);
	};
	// > d, when will x be hit
	auto behit = [&](int x, ll d) {
		if (cid[x] == 0) return inf;
		ll a = d % csz[x], b = cpos[x];
		if (a <= b) return d + b - a;
		return d + csz[x] - a + b;
	};
	auto upd = [&](int x, ll d) {
		auto &A = dp[x][0], &B = dp[x][1];
		bool ch = false;
		if (d < A) {
			putin(d, x);
			swap(d, A);
			ch = true;
		}
		if (cid[x] == 0) return;
		if (d > behit(x, A) && d < B) {
			if (!ch) putin(d, x);
			swap(B, d);
		}
	};

	upd(1, 0);

	// when x's shortest path is d, I want to relax u

	auto valid = [&](int x, ll d, int u) {
		if (cid[u] == 0) return true;
		if (d % csz[u] == cpos[u]) return false;
		if (cid[x] == cid[u] && cpos[u] == (cpos[x] - 1 + csz[x]) % csz[u]) {
			if (d % csz[u] == cpos[x]) return false;
		}
		return true;
	};

	auto relax = [&](int x, int u, ll d) {
		if (cid[u] == 0) {
			upd(u, d+1);
			return;
		};

		DE(x, u, d);
		if (valid(x, d+1, u))
			upd(u, d+1);
		else if (valid(x, d+1, x) && valid(x, d+2, u))
			upd(u, d+2);

		ll xh = behit(x, d), uh = behit(u, d);
		if (xh <= uh + 1) return;
		DE(xh, uh, x, u, d);
		upd(u, uh + 1);
	};

	// shortest path
	for (int d = 0;d < q.size();++d) {
		for (int i = 0;i < q[d].size();++i) {
			int x = q[d][i];
			if (d != dp[x][0] && d != dp[x][1]) continue;

			if (cid[x]) assert(d % csz[x] != cpos[x]);

			DE(d, x);
			for (int u : edge[x])
				relax(x, u, d);
		}
	}

	ll res = inf;
	for (auto v : dp[n]) chmin(res, v);
	
	if (res == inf) cout << "impossible\n";
	else cout << res << '\n';
}

컴파일 시 표준 에러 (stderr) 메시지

watchmen.cpp: In lambda function:
watchmen.cpp:62:16: warning: comparison of integer expressions of different signedness: 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   62 |   if (q.size() < d + 1) q.resize(d + 1);
      |       ~~~~~~~~~^~~~~~~
watchmen.cpp: In lambda function:
watchmen.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
watchmen.cpp:106:3: note: in expansion of macro 'DE'
  106 |   DE(x, u, d);
      |   ^~
watchmen.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
watchmen.cpp:114:3: note: in expansion of macro 'DE'
  114 |   DE(xh, uh, x, u, d);
      |   ^~
watchmen.cpp: In function 'int32_t main()':
watchmen.cpp:119:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  119 |  for (int d = 0;d < q.size();++d) {
      |                 ~~^~~~~~~~~~
watchmen.cpp:120:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |   for (int i = 0;i < q[d].size();++i) {
      |                  ~~^~~~~~~~~~~~~
watchmen.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
watchmen.cpp:126:4: note: in expansion of macro 'DE'
  126 |    DE(d, x);
      |    ^~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20