Submission #976246

#	Time	Username	Problem	Language	Result	Execution time	Memory
976246		Amaarsaa	Dreaming (IOI13_dreaming)	C++14	100 / 100	55 ms	17640 KiB

dreaming

#include<bits/stdc++.h>
#include "dreaming.h"
using namespace std;
vector < pair < int , int > > adj[100005];
int d[100004], used[100004];
int to[100005];
void dfs(int node, int parent, int dist) {
	d[node] = 0;
	to[node] = -1;
	used[node] = 1;
	for ( pair < int, int >& A : adj[node]) {
		int child = A.first;
		if ( child == parent) continue;
		dfs(child, node, dist + A.second);
		if ( d[node] < d[child] + A.second) {
			d[node] = d[child] + A.second;
			to[node] = child;
		}
	}
}
int ans = 0;
vector < int > Ans;
void Go(int x) {
	int y;
	dfs(x, x, 0);
	while(to[x] != -1) x = to[x];
	y = x;
	dfs(x, x, 0);
	int dist = d[x];
	vector < int > v;
	while (to[x] != -1) {
		v.push_back(x);
		x = to[x];
	}
	v.push_back(x);
	int s = 2e9;
	for ( int X : v) {
		s = min(s, max(d[X], dist -d[X])); 
	}
	ans = max(ans, dist);
	Ans.push_back(s);
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	for (int i = 0; i < M; i ++) {
		adj[A[i]].push_back({B[i], T[i]});
		adj[B[i]].push_back({A[i], T[i]});
	}
	for (int i = 0; i < N; i ++) {
		if (!used[i]) {
			Go(i);
		}
	}
	sort(Ans.rbegin(), Ans.rend());
	if ( Ans.size() == 1) return ans;
	if ( Ans.size() == 2) return max(ans, Ans[0] + Ans[1] + L);
	return max(ans, max(Ans[0] + Ans[1] + L, Ans[1] + Ans[2] + 2 *L));
}

Compilation message (stderr)

dreaming.cpp: In function 'void Go(int)':
dreaming.cpp:24:6: warning: variable 'y' set but not used [-Wunused-but-set-variable]
   24 |  int y;
      |      ^

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