Submission #582044

#	Time	Username	Problem	Language	Result	Execution time	Memory
582044		8e7	Highway Tolls (IOI18_highway)	C++17	90 / 100	371 ms	19832 KiB

highway

#include "highway.h"
//Challenge: Accepted
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
	while (l != r) cout << *l << " ", l++;
	cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 100005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
vector<pii> adj[maxn], g[maxn];

ll mind;
vector<int> tmp;
int ord[maxn];
void dfs(int n, int par, int &cur, int lim) {
	ord[cur++] = n;	
	if (cur > lim) return;
	for (auto [v, id]:adj[n]) {
		//debug(n, v);
		if (v != par && cur + 1 <= lim) {
			tmp[id] = 0;
			//debug("edge", n, v);
			dfs(v, n, cur, lim);
			if (cur > lim) return;
		} 
	}
}

int m, edges;
void getnode(int n, int par, int &cur, int d, vector<int> &vec) {
	cur++;
	if (d == edges) {
		vec.push_back(cur);
	}
	for (auto [v, id]:adj[n]) {
		if (v != par) {
			getnode(v, n, cur, d+1, vec);
		}
	}
}

int type = 0;
int getind(int n, int root) {
	int low = 0, up = n;
	vector<int> poss;
	if (type == 1) {
		int ini = 0;
		getnode(root, -1, ini, 0, poss);
		up = poss.size();	
	}
	pary(poss.begin(), poss.end());
	tmp.resize(m, 0);	

	dfs(root, -1,low, 1<<30); 
	low = -1;
	while (low < up - 1) {
		int mid = (low + up) / 2;
		for (int i = 0;i < m;i++) tmp[i] = 1;
		int ini = 0;
		if (type) dfs(root, -1, ini, poss[mid]);
		else dfs(root, -1, ini, mid); 

		//debug(low, mid, up);
		//pary(tmp.begin(), tmp.end());
		ll val = ask(tmp);
		if (val == mind) {
			up = mid;	
		} else {
			low = mid;
		}
	}
	//debug(up, ord[up-1]);
	return (type ? ord[poss[up] - 1] : ord[low]);
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
	int M = U.size();
	m = M;

	vector<int> ini(M, 0);
	mind = ask(ini);
	edges = mind / A;
	int low = 0, up = M;	
	while (low < up - 1) {
		int mid = (low + up) / 2;
		for (int i = 0;i < M;i++) {
			if (i < mid) ini[i] = 0;
			else ini[i] = 1;
		}
		if (ask(ini) == mind) {
			up = mid;
		} else {
			low = mid;
		}
	}

	for (int i = 0;i < M;i++) {
		g[U[i]].push_back({V[i], i});
		g[V[i]].push_back({U[i], i});
	}

	//debug(low, U[low], V[low]);
	vector<bool> vis(N, 0);
	int root = U[low];	
	queue<int> que;
	que.push(root);
	vis[root] = 1;
	while (que.size()) {
		int cur = que.front();que.pop();
		vis[cur] = 1;
		for (auto [v, id]:g[cur]) {
			if (!vis[v]) {
				vis[v] = 1;
				adj[cur].push_back({v, id});
				adj[v].push_back({cur, id});
				que.push(v);
			}
		}
	}
	
	int s = getind(N, root);
	type = 1;
	int t = getind(N, s);
	debug(s, t);
	answer(s, t);
}
/*
4 3 5 8 1 3
0 1
0 2
1 3
*/

Compilation message (stderr)

highway.cpp: In function 'int getind(int, int)':
highway.cpp:14:19: warning: statement has no effect [-Wunused-value]
   14 | #define pary(...) 0
      |                   ^
highway.cpp:63:2: note: in expansion of macro 'pary'
   63 |  pary(poss.begin(), poss.end());
      |  ^~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:13:20: warning: statement has no effect [-Wunused-value]
   13 | #define debug(...) 0
      |                    ^
highway.cpp:135:2: note: in expansion of macro 'debug'
  135 |  debug(s, t);
      |  ^~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 21 / 31