Submission #787999

#	Time	Username	Problem	Language	Result	Execution time	Memory
787999		allin27x	Dreaming (IOI13_dreaming)	C++17	18 / 100	108 ms	43320 KiB

dreaming

#include <bits/stdc++.h>
using namespace std;
#include "dreaming.h"

int ds[2][(int)1e5];
unordered_map<int,int> adj[(int)1e5];
int vis[(int)1e5];
int ind = 0;
unordered_set<int> sets[(int)1e5];
int cp[(int)1e5];

void dfs(int i , int p, int len, int x){
	sets[ind].insert(i);
	vis[i] = 1;
	ds[x][i] = len;
	for (auto const &pair: adj[i]){
		int c = pair.first; int w= pair.second;
		if (c==p) continue;
		dfs(c,i, len+w,x);
	}
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]){
	for (int i=0; i<M; i++){
		int a = A[i]; int b = B[i];
		adj[a][b] = T[i]; adj[b][a] = T[i];
	}
	int r;
	for (int i=0; i<N; i++){
		if (vis[i]) continue;
		dfs(i,i,0,0);
		int a1 = i;
		for (auto c: sets[ind]){
			if (ds[0][c]>ds[0][a1]) a1 = c;
		}
		dfs(a1,a1,0,0);
		int a2 = a1;
		r = a1;
		for (auto c: sets[ind]){
			if (ds[0][c]>ds[0][a2]) a2 = c;
		}
		dfs(a2,a2,0,1);
		int ans = 1e7;
		for (auto c: sets[ind]){
			ans = min(ans, max(ds[0][c], ds[1][c]));
		}
		if (ans!=1e7) cp[ind] = ans; else cp[ind] = 0;
		ind++;
	}
	if (ind == 1){
		return ds[1][r];
	}
	sort(cp, cp+ind);
	if (ind ==2 ) return L + cp[ind-1] + cp[ind-2];
	return max(L + cp[ind-1] + cp[ind-2], 2*L + cp[ind-2] + cp[ind-3]);
}

// int main(){
// 	int n = 12; int m = 8 ;
// 	int l = 2;
// 	int a[] = {0, 8, 2, 5, 5, 1, 1, 10};
// 	int b[] = {8, 2, 7, 11, 1, 3, 9, 6};
// 	int t[] = {4, 2, 4, 3, 7, 1, 5, 3};
// 	cout<<travelTime(n,m,l,a,b,t);
// }

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:51:17: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   51 |   return ds[1][r];
      |                 ^

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