Submission #518958

#	Time	Username	Problem	Language	Result	Execution time	Memory
518958		fabijan_cikac	Race (IOI11_race)	C++17	0 / 100	3 ms	4940 KiB

race

#include <bits/stdc++.h>

using namespace std;

typedef long long int ll;
typedef pair<int, int> pp;

const int MAXN = 2 * 1e5 + 100;
const int INF = 1e9;

struct mapa{
    int val = INF;
};

int n, k;
vector<pp> v[MAXN];
int p[MAXN] = { 0 };
int vel[MAXN] = { 0 };
map<int, mapa> m;
vector<int> s;
int sol = INF;
int cnt = 0;

int dfs(int x, int depth, int sum, int val){
    p[x] = 1;
    if (val == 0)
        ++cnt;
    else if (val == 1 && sum <= k && m[k - sum].val != INF){
        int zb = depth + m[k - sum].val - 1;
        sol = min(sol, zb);
    }
    else if (val == 2 && sum <= k){
        s.push_back(sum);
        m[sum].val = min(m[sum].val, depth);
    }
    for (int i = 0; i < v[x].size(); ++i){
        int y = v[x][i].first;
        if (!p[y]){
            int rt = dfs(y, depth + 1, sum + v[x][i].second, val);
            if (val == 0)
                vel[x] += rt;
        }
    }
    if (val == 0)
        ++vel[x];
    p[x] = 0;
    if (val == 0)
        return vel[x];
    return 0;
}

int centr(int x){
    pp maks = {-1, -1};
    for (int i = 0; i < v[x].size(); ++i){
        int y = v[x][i].first;
        if (!p[y] && vel[y] > maks.second)
            maks = {y, vel[y]};
    }
    if (maks.second <= cnt / 2)
        return x;
    return maks.first;
}

void solve(int x){
    for (int i = 0; i < v[x].size(); ++i){
        int y = v[x][i].first;
        if (!p[y]){
            dfs(y, 2, v[x][i].second, 1); dfs(y, 2, v[x][i].second, 2);
        }
    }
    for (int i = 0; i < s.size(); ++i)
        m[s[i]].val = INF;
    s.clear(); return;
}

void decompose(int x){
    cnt = 0; dfs(x, 1, 0, 0);
    int root = centr(x); p[root] = 1;
    solve(root);
    for (int i = 0; i < v[root].size(); ++i){
        int y = v[root][i].first;
        if (!p[y]) decompose(y);
    }
}

int best_path(int N, int K, int H[MAXN][2], int L[MAXN]){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    for (int i = 0; i < N - 1; ++i){
        v[H[i][0]].push_back({H[i][1], L[i]});
        v[H[i][1]].push_back({H[i][0], L[i]});
    }
    decompose(0);
    if (sol == INF)
        cout << -1;
    else cout << sol - 1;

    return 0;
}

Compilation message (stderr)

race.cpp: In function 'int dfs(int, int, int, int)':
race.cpp:36:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     for (int i = 0; i < v[x].size(); ++i){
      |                     ~~^~~~~~~~~~~~~
race.cpp: In function 'int centr(int)':
race.cpp:54:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |     for (int i = 0; i < v[x].size(); ++i){
      |                     ~~^~~~~~~~~~~~~
race.cpp: In function 'void solve(int)':
race.cpp:65:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |     for (int i = 0; i < v[x].size(); ++i){
      |                     ~~^~~~~~~~~~~~~
race.cpp:71:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |     for (int i = 0; i < s.size(); ++i)
      |                     ~~^~~~~~~~~~
race.cpp: In function 'void decompose(int)':
race.cpp:80:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |     for (int i = 0; i < v[root].size(); ++i){
      |                     ~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57