Submission #1030882

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030882		Hectorungo_18	City Mapping (NOI18_citymapping)	C++14	25 / 100	21 ms	652 KiB

citymapping

#include "citymapping.h"
#include <bits/stdc++.h>
using namespace std;
 
 
const int N = 1e3+5;
vector<int> adj[N];
int v[N], r[N], w[N]; 
vector<pair<long long int, int>> dis(N, {1e18+7, 0});
int pos = 0;
 
 
 
void un(int a, int b, int dis){
    adj[a].push_back(b);
    // adj[b].push_back(a);
    v[pos]=a;
    r[pos]=b;
    w[pos]=dis;
    pos++;
}
 
 
void dfs(int u, int p, int ps, long long int pd){
    int st = dis[ps].second, dd = dis[ps].first;
 
    if(adj[u].size() == 0){
        un(u, st, (int) pd);
        return;
    }
 
    if(adj[u].size() == 1){
        int x = adj[u][0];
        long long int d = get_distance(x, st);
        if(d < pd) dfs(x, u, ps, d);
        else{
            un(u, st, (int) pd);
            return;
        }
		return;
    }
 
    if(adj[u].size() == 2){
        int x = adj[u][0];
		int y = adj[u][1];
		int g = rand()%2;
		if(g) swap(x, y);

        long long int d = get_distance(x, st);
        
        if(d < pd) dfs(x, u, ps, d);
        else{
            long long int r = get_distance(y, st);
            dfs(y, u, ps, r);
        }
		return;
    }
 
    
 
}
 
 
void find_roads(int n, int q, int A[], int B[], int W[]) {
    // vector<pair<long long int, int>> dis (n-1);
	long long int mx;
	int mp;
	mx = -1;
  mp = -1;
    for(int i = 0; i < n-1; i++){
        long long int d = get_distance(1, i+2);
        // dis[i]={d, i+2};
		if(d > mx){
			mx = d;
			mp=i+2;
		}
    }
	int rr = 0;
	for(int i = 0; i < n; i++){
		if(i+1 != mp){
			long long int d = get_distance(mp, i+1);
			dis[i-rr]={d, i+1};
		}
		else rr=1;
	}
    sort(dis.begin(), dis.end());
 
    
    un(mp, dis[0].second, dis[0].first);
 
    for(int i = 1; i < n-1; i++){
        dfs(mp, -1, i, dis[i].first);
    }
 
    // for(int i = 0; i < n-1; i++){
    //     cout << v[i] << " " << r[i] << " " << w[i] << endl;
    // }
    //int aa[n-1], bb[n-1], cc[n-1];
 
 
    // for(int i = 0; i < n-1; i++){
    //     aa[i] = v[i];
    //     bb[i] = r[i];
    //     cc[i] = w[i];
    //     // cout << v[i] << " " << r[i] << " " << w[i] << endl;
    // }
    // A = aa;
    // B = bb;
    // W = cc;
 
	for (int i = 0; i < n - 1; i++) {
		A[i] = v[i];
		B[i] = r[i];
		W[i] = w[i];
		// cout << A[i] << " " << B[i] << " " << W[i] << endl;
	}
	return;
}

Compilation message (stderr)

citymapping.cpp: In function 'void dfs(int, int, int, long long int)':
citymapping.cpp:25:30: warning: unused variable 'dd' [-Wunused-variable]
   25 |     int st = dis[ps].second, dd = dis[ps].first;
      |                              ^~

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 0 / 13
• Subtask 4: 0 / 19
• Subtask 5: 0 / 43