Submission #418831

#	Time	Username	Problem	Language	Result	Execution time	Memory
418831		Maqsut_03	Race (IOI11_race)	C++14	100 / 100	1357 ms	51408 KiB

race

#include "race.h"
#include <bits/stdc++.h>
 
#define N 200200
using namespace std;
 
vector<pair<int, int> > g[N];
int d[N];
//int p[N];
 
int get_centroid(int v, int parent, int n, int &centroid) {
    int size = 1;
    for (auto[x, y]:g[v]) {
        if (x != parent && d[x] == -1) {
            size += get_centroid(x, v, n, centroid);
        }
    }
    if (size * 2 >= n && centroid == -1) centroid = v;
    return size;
}
 
int K;
int ans = 1e9;
 
void get_compo_dists(int v, int dist, int len, int pass_limit, vector<pair<int, int> > &vec, int p = -1) 
{
    if (dist > K) return;
    vec.emplace_back(dist, len);
    
    for (auto[x, y]:g[v]) 
        if ((d[x] > pass_limit || d[x] == -1) && p != x) 
            get_compo_dists(x, dist + y, len + 1, pass_limit, vec, v);
}
 
void build(int v, int parent, int depth, int n) 
{
    int centroid = -1;
    get_centroid(v, -1, n, centroid);
    if (centroid == -1) centroid = v;
    d[centroid] = depth;
//    p[centroid] = parent;
    map<int, int> dist;
    dist[0] = 0;
 
    for (auto[x, y]:g[centroid]) 
        if (d[x] == -1) 
		{
            vector<pair<int, int>> vec;
            get_compo_dists(x, y, 1, d[centroid], vec);
            
			for (auto[distance, cost]: vec) 
                if (dist.count(K - distance)) 
                    ans = min(ans, cost + dist[K - distance]);
 
            for (auto[distance, cost]: vec)
                if (dist.count(distance) == 0) 
                    dist[distance] = cost;
				else dist[distance] = min(dist[distance], cost);
            
			build(x, centroid, depth + 1, (n + 1) / 2);
        }
}
 
int best_path(int n, int K, int H[][2], int L[]) 
{
    ::K = K;
    for (int i = 0; i < n - 1; i++)
	{
        g[H[i][0]].emplace_back(H[i][1], L[i]);
        g[H[i][1]].emplace_back(H[i][0], L[i]);
    }
    fill(d, d + N, -1);
    build(0, -1, 1, n);
 
    return (ans == 1e9 ? -1 : ans);
}
 

Compilation message (stderr)

race.cpp: In function 'int get_centroid(int, int, int, int&)':
race.cpp:13:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   13 |     for (auto[x, y]:g[v]) {
      |              ^
race.cpp: In function 'void get_compo_dists(int, int, int, int, std::vector<std::pair<int, int> >&, int)':
race.cpp:30:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   30 |     for (auto[x, y]:g[v])
      |              ^
race.cpp: In function 'void build(int, int, int, int)':
race.cpp:45:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   45 |     for (auto[x, y]:g[centroid])
      |              ^
race.cpp:51:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   51 |    for (auto[distance, cost]: vec)
      |             ^
race.cpp:55:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   55 |             for (auto[distance, cost]: vec)
      |                      ^

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57