Submission #468158

#	Time	Username	Problem	Language	Result	Execution time	Memory
468158		SirCovidThe19th	Dreaming (IOI13_dreaming)	C++17	100 / 100	86 ms	17156 KiB

dreaming

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

#define pii pair<int, int>
#define f first
#define s second

const int mx = 1e5 + 5, inf = 1e9;

vector<pair<int, int>> adj[mx]; pii in[mx]; bool vis[mx]; int lg;

void comb(pii &p, int x){
	if (x > p.f) p.s = p.f, p.f = x;
	else if (x > p.s) p.s = x;
}
void dfs1(int i, int p){
    vis[i] = 1;
    for (auto [x, w] : adj[i]) if (x != p){
        dfs1(x, i); 
		comb(in[i], in[x].f + w);
    }
}
void dfs2(int i, int p, int pout, int &mnD){
    mnD = min(mnD, max(pout, in[i].f)); lg = max(lg, in[i].f + pout);
    for (auto [x, w] : adj[i]) if (x != p){
        int sib = (in[i].f == in[x].f + w) ? in[i].s : in[i].f;
        int out = max(sib, pout) + w;
        dfs2(x, i, out, mnD);
    }
}
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]});
    }
    int w[3] = {-l, -l, -l};
    for (int i = 0; i < n; i++) if (!vis[i]){
        int mnD = 1e9; dfs1(i, 0); dfs2(i, 0, 0, mnD);
		if (mnD > w[0]) w[2] = w[1], w[1] = w[0], w[0] = mnD;
		else if (mnD > w[1]) w[2] = w[1], w[1] = mnD;
		else if (mnD > w[2]) w[2] = mnD;
    }
	if (n == 1) return 0;
	if (n == 2) return m ? T[0] : l;
	return max({w[0] + w[1] + l, w[1] + w[2] + 2 * l, lg});
}

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