Submission #1168713

#	Time	Username	Problem	Language	Result	Execution time	Memory
1168713		Br3ad	City Mapping (NOI18_citymapping)	C++20	0 / 100	17 ms	580 KiB

citymapping

#include <iostream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <numeric>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include "citymapping.h"

using namespace std;
#define ll long long
#define ull unsigned long long
#define f first
#define s second
#define PF push_front
#define PB push_back
#define MP make_pair

#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()

#define max(a, b) ((a > b)? a : b)
#define min(a, b) ((a < b)? a : b)
#define max3(a, b, c) max(max(a, b), c)
#define min3(a, b, c) min(min(a, b), c)

const int N = 1e3 + 5;
const int M = 1e9 + 7; 
const int inf = 0x3f3f3f3f;
const ll int INF = 1e18;

// ll get_distance(int x, int y){
//     int dis[6][6];
//     dis[1][2] = 9;
//     dis[1][3] = 15;
//     dis[1][4] = 8;
//     dis[1][5] = 18;
//     dis[2][3] = 8;
//     dis[2][4] = 1;
//     dis[2][5] = 11;
//     dis[3][4] = 7;
//     dis[3][5] = 3;
//     dis[4][5] = 10;
//     if(x > y) swap(x, y);
//     return dis[x][y];
// }

vector<vector<pair<int, int>>> adj(1005, vector<pair<int, int>>());
vector<int> sz(1005);
vector<bool> block(1005, false);

void get_sz(int cur){
    sz[cur] = 1;
    for(auto [child, _] : adj[cur]){
        if(block[child]) continue;
        get_sz(child);
        sz[cur] += sz[child];
    }
}

void find_roads(int n, int q, int a[], int b[], int w[]){
    vector<pair<ll, int>> dis;
    vector<ll> dis_to(n+1);
    for(int i = 2; i <= n; i++){
        ll temp = get_distance(1, i);
        dis.PB(MP(temp, i));
        dis_to[i] = temp;
    }

    sort(all(dis));
    adj[1].PB(MP(dis[0].s, dis[0].f));

    vector<bool> added(n+1, false);
    added[1] = true;
    added[dis[0].s] = true;
    
    for(int i = 1; i < n-1; i++){
        int root = 1;
        int cur = dis[i].s;
        while(true){
            for(int j = 1; j <= n; j++) sz[j] = 0;
            get_sz(root);

            if(sz[root] == 1) break;

            int mid = root;
            for(int j = 1; j <= n; j++) if(sz[j] > 0){
                int dif = abs(sz[j] - (sz[root]/2));
                if(dif < abs(sz[mid] - (sz[root]/2))){
                    mid = j;
                }
            }

            int dist = get_distance(cur, mid);
            if(dis_to[mid] + dist == dis_to[cur]){
                // Correct subtree
                root = mid;
            }else {
                block[mid] = true;
            }
        }
        
        adj[root].PB(MP(cur, dis_to[cur] - dis_to[root]));
    }

    int cnt = 0;
    for(int i = 1; i <= n; i++){
        for(auto [child, weight] : adj[i]){
            a[cnt] = i;
            b[cnt] = child;
            w[cnt] = weight;
            cnt++;
        }
    }
}

// int main(){
//     
//     ios::sync_with_stdio(false);
//     cin.tie(NULL);
//     
//     // ifstream cin();
//     // ofstream cout();
//     
//     const int sz = 5;
//     int a[sz], b[sz], w[sz];
//     find_roads(5, 50000, a, b, w);
//     
//     for(int i = 0; i < sz-1; i++){
//         cout << a[i] << ' ' << b[i] << ' ' << w[i] << endl;
//     }
// }

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