Submission #103475

#	Time	Username	Problem	Language	Result	Execution time	Memory
103475		figter001	Simurgh (IOI17_simurgh)	C++17	13 / 100	28 ms	4344 KiB

simurgh

#include "simurgh.h"
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
const int nax = 250;

int dsu[nax];
int m,n;
bool used[nax];
vector<pair<int,int>> g[nax];
vector<int> u,v;

int find(int u){
	return u == dsu[u] ? u : dsu[u] = find(dsu[u]);
}

bool good(vector<int> ans){
	for(int i=0;i<n;i++)
		dsu[i] = i;
	for(int i=0;i<ans.size();i++){
		int id = ans[i];
		int a = u[id];
		int b = v[id];
		if(find(a) == find(b))
			continue;
		dsu[find(b)] = find(a);
	}
	for(int i=0;i<n;i++)
		if(find(i) != find(0))
			return 0;
	return 1;
}

vector<int> find_roads(int N, vector<int> U, vector<int> V) {
	vector<int> ans;
	u = U;
	v = V;
	n = N;
	m = u.size();

	for(int i=0;i<n;i++)
		dsu[i] = i;

	int lst;
	for(int i=0;i<m;i++){
		int a = u[i];
		int b = v[i];
		g[a].push_back({b,i});
		g[b].push_back({a,i});
		if(find(a) == find(b))
			continue;
		used[i] = 1;
		ans.push_back(i);
		dsu[find(b)] = find(a);
	}
	lst = count_common_roads(ans);
	for(int i=0;i<ans.size();i++){
		int id = ans[i];
		int a = u[id];
		int b = v[id];
		for(int j=0;j<m;j++){
			if(used[j])
				continue;
			ans[i] = j;
			if(good(ans) == 1){
				int r = count_common_roads(ans);
				if(r < lst){
					ans[i] = id;
					break;
				}
				if(r > lst){
					lst = r;
					used[j] = 1;
					used[id] = 0;
					break;
				}
			}
			ans[i] = id;
		}
	}
	// for(int i : ans)
	// 	printf("%d ", i);
	// printf("\n");
	return ans;
}

Compilation message (stderr)

simurgh.cpp: In function 'bool good(std::vector<int>)':
simurgh.cpp:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<ans.size();i++){
              ~^~~~~~~~~~~
simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:61:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<ans.size();i++){
              ~^~~~~~~~~~~
simurgh.cpp:63:7: warning: unused variable 'a' [-Wunused-variable]
   int a = u[id];
       ^
simurgh.cpp:64:7: warning: unused variable 'b' [-Wunused-variable]
   int b = v[id];
       ^

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