Submission #1107361

#	Time	Username	Problem	Language	Result	Execution time	Memory
1107361		thieunguyenhuy	Highway Tolls (IOI18_highway)	C++17	18 / 100	634 ms	59500 KiB

highway

#ifndef hwe
	#include "highway.h"
#endif
 
#include <bits/stdc++.h>
using namespace std;
 
#define popcount(n) (__builtin_popcountll((n)))
#define clz(n) (__builtin_clzll((n)))
#define ctz(n) (__builtin_ctzll((n)))
#define lg(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
 
#define Int __int128
#define fi first
#define se second
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
 
template <class T1, class T2>
bool maximize(T1 &x, T2 y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
template <class T1, class T2>
bool minimize(T1 &x, T2 y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
 
template <class T>
void remove_duplicate(vector<T> &ve) {
    sort (ve.begin(), ve.end());
    ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
 
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
template <class T> T random(T l, T r) {
    return uniform_int_distribution<T>(l, r)(rng);
}
template <class T> T random(T r) {
    return rng() % r;
}
 
const int N = 90000 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const ll INF = 1e18;
 
const int LIGHT = 0, HEAVY = 1;
 
int asked = 0, dist[2][N], e[N];
vii adj[N];
vector<int> ve[N];
map<vector<int>, ll> mem;
bitset<N> inSet;

#ifdef hwe
namespace Grader {
	int n, m, s, t;
	ll dist[N];
	pii edges[N];
	vii adj[N];
	vector<int> w;
 
	void get() {
		cin >> n >> m >> s >> t;
	
		for (int i = 0; i < m; ++i) {
			int u, v; cin >> u >> v;
			adj[u].emplace_back(v, i), adj[v].emplace_back(u, i);
			edges[i] = make_pair(u, v);
		}
	}
 
	void rand() {
		n = random(7, 10), m = random(n - 1, 20), s = random(n), t = random(n);
		while (s == t) t = random(n);
		for (int i = 1; i < n; ++i) {
			edges[i - 1] = make_pair(random(i), i);
		}
		for (int i = n - 1; i < m; ++i) {
			edges[i] = make_pair(random(n), random(n));
		}
		for (int i = 0; i < n; ++i) adj[i].clear();
		for (int i = 0; i < m; ++i) {
			int u, v; tie(u, v) = edges[i];
			adj[u].emplace_back(v, i), adj[v].emplace_back(u, i);
		}
	}
 
	void show() {
		cerr << n << ' ' << m << ' ' << s << ' ' << t << '\n';
		for (int i = 0; i < m; ++i) cerr << edges[i].fi << ' ' << edges[i].se << '\n';
	}
 
	ll dijkstra(int s, int t) {
		memset(dist, 0x0f, sizeof dist); dist[s] = 0;
		priority_queue<pli, vli, greater<pli>> pq; pq.emplace(0, s);
		while (!pq.empty()) {
			int u = pq.top().se; pq.pop();
			// cerr << "dijkstra " << u << ' ' << dist[u] << '\n';
			for (auto [v, id] : adj[u]) if (minimize(dist[v], dist[u] + w[id])) {
				pq.emplace(dist[v], v);
			}
		}
		int ma = -1; for (auto &x : w) maximize(ma, x);
		if (ma <= 1) cerr << "kq " << dist[t] << '\n';
		return dist[t];
	}
 
	ll ask(const vector<int> &_w) {
		w = _w; for (auto &x : w) ++x;
		return dijkstra(s, t);
	}
}
 
ll ask(const vector<int> &w) {
	return Grader::ask(w);
}
 
void answer(int s, int t) {
	cerr << "Answer " << s << ' ' << t << '\n';
}
#endif
 
ll myask(const vector<int> &w) {
	auto it = mem.find(w);
	if (it != mem.end()) return it->se;
	assert(++asked <= 50);
	return mem[w] = ask(w);
}
 
void bfs(const int type, int root) {
	memset(dist[type], -1, sizeof dist[type]); dist[type][root] = 0;
	queue<int> q; q.emplace(root);
	while (!q.empty()) {
		int u = q.front(); q.pop();
		for (auto [v, id] : adj[u]) if (dist[type][v] == -1) {
			dist[type][v] = dist[type][u] + 1, e[v] = id;
			q.emplace(v);
		}
	}
}

void print(vector<int> &ve) {
	for (auto &x : ve) cerr << x << ' ';
	cerr << '\n';
}
 
void find_pair(int n, vector<int> U, vector<int> V, int A, int B) {
	int m = U.size(); asked = 0;
	for (int i = 0; i < n; ++i) adj[i].clear();
	for (int i = 0; i < m; ++i) {
		adj[U[i]].emplace_back(V[i], i), adj[V[i]].emplace_back(U[i], i);
	}
 
	vector<int> w(m, LIGHT); mem.clear();
	ll fixed = myask(w); int numEdges = fixed / A;

	int low = 0, high = m - 1, edgeId = -1;
	while (low <= high) {
		int mid = low + high >> 1; vector<int> w(m, HEAVY);
		for (int i = 0; i <= mid; ++i) w[i] = LIGHT;
		if (myask(w) < 1ll * numEdges * B) high = (edgeId = mid) - 1;
		else low = mid + 1;
	}
	int u = U[edgeId], v = V[edgeId];

	cerr << "EdgeId " << edgeId << '\n';
	
	bfs(0, u), bfs(1, v); e[u] = e[v] = edgeId; vector<int> S, T;
	for (int i = 0; i < n; ++i) {
		if (dist[0][i] < dist[1][i]) S.emplace_back(i);
		else if (dist[0][i] > dist[1][i]) T.emplace_back(i);
	}

	sort (S.begin(), S.end(), [&](int x, int y) {
		return dist[0][x] < dist[0][y];
	});
	sort (T.begin(), T.end(), [&](int x, int y) {
		return dist[1][x] < dist[1][y];
	});

	cerr << "S: "; print(S);
	cerr << "T: "; print(T);

	for (auto &x : T) cerr << e[x] << ' ';
	cerr << '\n';

	auto work = [&](const int type, const vector<int> &ve) {
		vector<int> w(m, HEAVY); for (auto &x : ve) w[e[x]] = LIGHT;
		ll fixed = myask(w);

		int low = 0, high = int(ve.size()) - 2, id = ve.size() - 1;
		while (low <= high) {
			int mid = low + high >> 1; vector<int> w(m, HEAVY);
			for (int i = 0; i <= mid; ++i) w[e[ve[i]]] = LIGHT;
			// if (mid == 1) cerr << "myask = " << myask(w) << '\n';
			if (myask(w) <= fixed) high = (id = mid) - 1;
			else low = mid + 1;
		}
		return id;
	};

	int idS = work(0, S), idT = work(1, T);
	cerr << idS << ' ' << idT << '\n';
	int s = S[idS], t = T[idT];
	answer(s, t);
}
 
#ifdef hwe
signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
 
    #ifdef hwe
        freopen("input.inp", "r", stdin);
        freopen("output.out", "w", stdout);
    #else
        #define taskname ""
        if (fopen(taskname".inp", "r")) {
            freopen(taskname".inp", "r", stdin);
            freopen(taskname".out", "w", stdout);
        }
    #endif
 
    // for (int _ = 0; _ < 1000; ++_) {
	//     Grader::rand(); Grader::show();
	//     int n = Grader::n; vector<int> U, V;
	//     for (int i = 0; i < Grader::m; ++i) {
	//     	int u, v; tie(u, v) = Grader::edges[i];
	//     	U.emplace_back(u), V.emplace_back(v);
	//     }
	//     find_pair(n, U, V, 1, 2);    	
    // }

    Grader::get(); Grader::show();
    int n = Grader::n; vector<int> U, V;
    for (int i = 0; i < Grader::m; ++i) {
    	int u, v; tie(u, v) = Grader::edges[i];
    	U.emplace_back(u), V.emplace_back(v);
    }
    find_pair(n, U, V, 1, 2);
 
    cerr << '\n'; return 0;
}
#endif

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:183:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  183 |   int mid = low + high >> 1; vector<int> w(m, HEAVY);
      |             ~~~~^~~~~~
highway.cpp: In lambda function:
highway.cpp:217:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  217 |    int mid = low + high >> 1; vector<int> w(m, HEAVY);
      |              ~~~~^~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31