Submission #809146

#	Time	Username	Problem	Language	Result	Execution time	Memory
809146		OAleksa	Dreaming (IOI13_dreaming)	C++14	14 / 100	40 ms	14360 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
 
#define f first
#define s second
using namespace std; 
const int maxn = 1e5 + 69;
vector<pair<int, int>> g[maxn];
vector<int> vis(maxn);
vector<int> d(maxn), par(maxn);
vector<int> t;
void dfs(int v, int p) {
	vis[v] = true;
	t.push_back(v);
	par[v] = p;
	for(auto u : g[v]) {
		if(u.f != p) {
			d[u.f] = d[v] + u.s;
			dfs(u.f, v);
		}
	}
}

int find_minmax(vector<int> &v, int dija)	{
	//v->cvorovi koji cine dijametar stabla
	int mn = 1e9, res = -1;
	for(auto x : v) {
		int y = max(d[x], dija - d[x]);
		if(mn >= y) {
			mn = y;
			res = x;
		}
	}
	return res;
}


int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
  for(int i = 0;i < M;i++) {
  	g[A[i]].push_back({B[i], T[i]});
  	g[B[i]].push_back({A[i], T[i]});
  }
  vector<int> r;
 	for(int i = 0;i < N - 1;i++) {
 		if(!vis[i]) {
 			t.clear();
 			dfs(i, -1);
 			int s, mx = 0;
 			for(auto x : t) {
 				if(d[x] >= mx) {
 					mx = d[x];
 					s = x;
 				}
 			}
 			t.clear();
 			d[s] = 0;
 			dfs(s, -1);
 			mx = 0;
 			for(auto x : t) {
 				if(d[x] >= mx) {
 					mx = d[x];
 					s = x;
 				}
 			}
 			vector<int> c;
 			while(s != -1) {
 				c.push_back(s);
 				s = par[s];
 			}
 			r.push_back(find_minmax(c, mx));
 		}
 	}
 	for(int i = 1;i < (int)r.size();i++) {
  	g[r[i]].push_back({r[i - 1], L});
  	g[r[i - 1]].push_back({r[i], L});
  }
  dfs(0, -1);
  int s, mx = 0;
	for(auto x : t) {
		if(d[x] >= mx) {
			mx = d[x];
			s = x;
		}
	}
	t.clear();
	d[s] = 0;
	dfs(s, -1);
	int ans = 0;
	for(int i = 0;i < N - 1;i++)
		ans = max(ans, d[i]);
	return ans;
}

//  
// int main()
// {
	  // ios_base::sync_with_stdio(false);
	  // cin.tie(0);
	  // cout.tie(0);
	  // int tt = 1;
		// //cin >> tt;
	  // while(tt--) {
			// int n, m, l;
			// cin >> n >> m >> l;
			// int a[m], b[m], t[m];
			// for(int i = 0;i < m;i++) 
				// cin >> a[i] >> b[i] >> t[i];
			// cout << travelTime(n, m, l, a, b, t);
		// }
    // return 0;
// }

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:87:5: warning: 'second' may be used uninitialized in this function [-Wmaybe-uninitialized]
   87 |  dfs(s, -1);
      |  ~~~^~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23