Submission #119119

#	Time	Username	Problem	Language	Result	Execution time	Memory
119119		MvC	Simurgh (IOI17_simurgh)	C++14	51 / 100	386 ms	4928 KiB

simurgh

#include "simurgh.h"
#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
const int N = 1024;
int was[N * N];
int w[N][N];
int f[N];
vi g[N];
pii dfs(int node) {
	for (auto it : g[node])
		if (f[it] == -1 && !was[w[node][it]]) {
			f[it] = node;
			auto cnt = dfs(it);
			if (cnt != mp(-1,-1))
				return cnt;
		}
		else
		if (f[node] != it && f[it] != -1 && !was[w[node][it]])
			return mp(node,it);
	return mp(-1,-1);
}
int p[N];
int Ws[N * N];
int get(int k) {
	return k == p[k] ? k : p[k] = get(p[k]);
} 
vi find_roads(int n,vi u,vi v) {
	int called = 0;
	int m = u.size();
	for (int i = 0;i < m;++i)
		w[u[i]][v[i]] = w[v[i]][u[i]] = i,g[u[i]].pb(v[i]),g[v[i]].pb(u[i]);
	vi answer;
	for (int i = 0;i < n;++i)
		p[i] = i;
	vi ee;
	for (int i = 0;i < m;++i)
		if (get(u[i]) != get(v[i])) {
			ee.pb(i);
			p[get(u[i])] = get(v[i]);
		}
	do {
		vi cycle;
		for (int i = 0;i < n;++i)
			f[i] = -1;
		f[0] = 0;
		auto cnt = dfs(0);
		if (cnt != mp(-1,-1)) {
			cycle.pb(w[cnt.fi][cnt.se]);
			for (int i = cnt.fi;i != cnt.se;i = f[i])
				cycle.pb(w[i][f[i]]);
		} else {
			int ok = 1;
			for (int i = 0;i < m;++i)
				if (Ws[i])
					ok &= !was[i];
			if (ok)
				break;
			else {
				for (int i = 0;i < m;++i)
					if (Ws[i])
						was[i] = 0;
			}
		}
		for (auto it : cycle)
			was[it] = 1;
		vector < pii > rs;
		int shit = 0;
		for (int i = 0;i < cycle.size();++i) {
				if (Ws[cycle[i]]) {
					++shit;
					if (shit > 1)
						continue;
				}
				for (int j = 0;j < n;++j)
					p[j] = j;
				vi e;
				for (int j = 0;j < cycle.size();++j)
					if (i != j) {
						p[get(u[cycle[j]])] = get(v[cycle[j]]);
						e.pb(cycle[j]);
					}
				for (auto it : ee)
					if (get(u[it]) != get(v[it])) {
						e.pb(it);
						p[get(u[it])] = get(v[it]);
					}
				rs.pb(mp(count_common_roads(e),cycle[i]));
			}
		int mn = min_element(all(rs))->fi;
		int mx = max_element(all(rs))->fi;
		if (mn != mx) {
			for (auto it : rs)
				if (it.fi == mn)
					Ws[it.se] = 1;
		}
	} while (1);
	for (int i = 0;i < m;++i)
		if (Ws[i] || (!Ws[i] && !was[i]))
			answer.pb(i);
	return answer;
}

Compilation message (stderr)

simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:81:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0;i < cycle.size();++i) {
                  ~~^~~~~~~~~~~~~~
simurgh.cpp:90:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j = 0;j < cycle.size();++j)
                    ~~^~~~~~~~~~~~~~
simurgh.cpp:41:6: warning: unused variable 'called' [-Wunused-variable]
  int called = 0;
      ^~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 17 / 17
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30