Submission #620873

#	Time	Username	Problem	Language	Result	Execution time	Memory
620873		8e7	Stations (IOI20_stations)	C++17	0 / 100	826 ms	668 KiB

stations

//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 1000
#define pii pair<int, int>
#define ff first
#define ss second
#include "stations.h"
const int mul = 501;

vector<int> adj[maxn];
int in[maxn], out[maxn], siz[maxn];
int tin, tout;
void getsiz(int n, int par) {
	siz[n] = 1;
	for (int v:adj[n]) {
		if (v != par) {
			getsiz(v, n);
			siz[n] += siz[v];
		}
	}
}
int getcentroid(int n, int par, int tot) {
	for (int v:adj[n]) {
		if (v != par && siz[v] * 2 > tot) {
			return getcentroid(v, n, tot);
		}
	}
	return n;
}
int dep[maxn];
void dfs(int n, int par, int d) {
	dep[n] = d;
	in[n] = tin++;
	siz[n] = 1;
	for (int v:adj[n]) {
		if (v != par) {
			dfs(v, n, d+1);
			siz[n] += siz[v];
		}
	}
	out[n] = tout++;
}
std::vector<int> label(int n, int LIM, std::vector<int> U, std::vector<int> V) {
	vector<int> ret(n);
	for (int i = 0;i < n;i++) {
		adj[i].clear();
		in[i] = 0, out[i] = 0;
		siz[i] = 0;
	}
	tin = tout = 0;

	for (int i = 0;i < n - 1;i++) {
		adj[U[i]].push_back(V[i]);
		adj[V[i]].push_back(U[i]);
	}
	getsiz(0, -1);
	int root = getcentroid(0, -1, n);
	
	dfs(root, -1, 0);
	for (int i = 0; i < n; i++) {
		if (dep[i] % 2 == 0) ret[i] = in[i] * 2 + 1;
		else ret[i] = out[i] * 2 + 2;
	}
	ret[root] = 0;
	pary(ret.begin(), ret.end());
	return ret;
}

const int inf = 1e9;
int find_next_station(int s, int t, std::vector<int> c) {
	int is, os, it, ot;
	if (s == 0) {
		is = 0, os = inf;
		int best = 0, bv = inf;
		t--;
		for (int v:c) {
			if (v/2 > t/2) {
				if (v/2 < bv) {
					bv = v/2;
					best = v;
				}
			}
		}
		return best;
	} else {
		s--;
		if (s % 2 == 0) { //in
			is = s/2;
			vector<int> tmp;
			for (int v:c) {
				if (v == 0) tmp.push_back(inf);
				else tmp.push_back(v/2);
			}
			sort(tmp.begin(), tmp.end());
			if (tmp.size() == 1) os = is;
			else os = tmp[tmp.size()-2]+1;
		} else {
			os = s/2;
			vector<int> tmp;
			for (int v:c) {
				if (v == 0) tmp.push_back(-inf);
				else tmp.push_back(v/2);
			}
			sort(tmp.begin(), tmp.end());
			if (tmp.size() == 1) is = os;
			else is = tmp[1]-1;
		}
	}

	if (t == 0) {
		for (int v:c) {
			if (v == 0) return v;
		}
		if (s%2 == 0) {
			return *max_element(c.begin(), c.end());
		} else {
			return *min_element(c.begin(), c.end());
		}
	} 
	t--;
	if (is <= t/2 && t/2 <= os) { //subtree
		if (s%2==0) {
			int best = 0, bv = inf;
			for (int v:c) {
				if (v == 0) continue;
				v--;
				debug(v/2, t/2);
				if (v/2 > t/2) {
					if (v/2 < bv) {
						bv = v/2;
						best = v;
					}
				}
			}
			return best;
		} else {
			int best = 0, bv = 0;
			for (int v:c) {
				if (v == 0) continue;
				v--;
				debug(v/2, t/2);
				if (v/2 < t/2) {
					if (v/2 > bv) {
						bv = v/2;
						best = v;
					}
				}
			}
			return best;
		}
	} else {
		for (int v:c) {
			if (v == 0) return v;
		}
		if (s%2 == 0) {
			return *max_element(c.begin(), c.end());
		} else {
			return *min_element(c.begin(), c.end());
		}
	}
	return 0;
}

Compilation message (stderr)

stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:13:19: warning: statement has no effect [-Wunused-value]
   13 | #define pary(...) 0
      |                   ^
stations.cpp:78:2: note: in expansion of macro 'pary'
   78 |  pary(ret.begin(), ret.end());
      |  ^~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:12:20: warning: statement has no effect [-Wunused-value]
   12 | #define debug(...) 0
      |                    ^
stations.cpp:140:5: note: in expansion of macro 'debug'
  140 |     debug(v/2, t/2);
      |     ^~~~~
stations.cpp:12:20: warning: statement has no effect [-Wunused-value]
   12 | #define debug(...) 0
      |                    ^
stations.cpp:154:5: note: in expansion of macro 'debug'
  154 |     debug(v/2, t/2);
      |     ^~~~~
stations.cpp:84:14: warning: unused variable 'it' [-Wunused-variable]
   84 |  int is, os, it, ot;
      |              ^~
stations.cpp:84:18: warning: unused variable 'ot' [-Wunused-variable]
   84 |  int is, os, it, ot;
      |                  ^~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61