Submission #433982

#	Time	Username	Problem	Language	Result	Execution time	Memory
433982		illyakr	Race (IOI11_race)	C++14	100 / 100	619 ms	37544 KiB

race

#include <iostream>
#include <vector>
#include "race.h"
using namespace std;

vector<pair<int, int> > g[200001];
int sz[200001];
bool del[200001];
void rcn(int v, int pred) {
    sz[v] = 1;
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to]) continue;
        rcn(to, v);
        sz[v] += sz[to];
    }
}
int centroid(int v, int pred, int N) {
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to])continue;
        if (sz[to] > N / 2)
            return centroid(to, v, N);
    }
    return v;
}
int Kur;
pair<int, int> have[1000001];
int res = 1010101010;
int ID;
void dfs(int v, int pred, int sum, int depth) {
    if (have[Kur - sum].first == ID)
        res = min(res, have[Kur - sum].second + depth);
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to] || sum + c > Kur)continue;
        dfs(to, v, sum + c, depth + 1);
    }
}
void put(int v, int pred, int sum, int depth) {
    if (have[sum].first == ID)
        have[sum].second = min(have[sum].second, depth);
    else {
        have[sum].first = ID;
        have[sum].second = depth;
    }
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to] || sum + c > Kur)continue;
        put(to, v, sum + c, depth + 1);
    }
}

void decomposition(int v) {
    del[v] = true;
    rcn(v, v);
    ID = v;
    have[0] = {v, 0};
    for (auto [to, c] : g[v]) {
        if (del[to] || c > Kur)continue;
        dfs(to, v, c, 1);
        put(to, v, c, 1);
    }
    for (auto [to, c] : g[v]) {
        if (del[to])continue;
        decomposition(centroid(to, v, sz[to]));
    }

}

int best_path(int N, int K, int H[][2], int L[]) {
    for (int i = 0; i < N - 1; i++) {
        g[H[i][0] + 1].push_back({H[i][1] + 1, L[i]});
        g[H[i][1] + 1].push_back({H[i][0] + 1, L[i]});
    }
    Kur = K;
    rcn(1, 1);
    decomposition(centroid(1, 1, N));
//    cout << centroid(1, 1, N) << " !!" << endl;

    if (res == 1010101010)return -1;
    return res;
}

/**
3 3
0 1 1
1 2 1
-1

11 12
0 1 3
0 2 4
2 3 5
3 4 4
4 5 6
0 6 3
6 7 2
6 8 5
8 9 6
8 10 7
2
*/

Compilation message (stderr)

race.cpp: In function 'void rcn(int, int)':
race.cpp:11:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   11 |     for (auto [to, c] : g[v]) {
      |               ^
race.cpp: In function 'int centroid(int, int, int)':
race.cpp:18:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   18 |     for (auto [to, c] : g[v]) {
      |               ^
race.cpp: In function 'void dfs(int, int, int, int)':
race.cpp:32:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   32 |     for (auto [to, c] : g[v]) {
      |               ^
race.cpp: In function 'void put(int, int, int, int)':
race.cpp:44:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   44 |     for (auto [to, c] : g[v]) {
      |               ^
race.cpp: In function 'void decomposition(int)':
race.cpp:55:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   55 |     for (auto [to, c] : g[v]) {
      |               ^
race.cpp:60:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   60 |     for (auto [to, c] : g[v]) {
      |               ^

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