Submission #538626

#	Time	Username	Problem	Language	Result	Execution time	Memory
538626		Sam_a17	Race (IOI11_race)	C++14	100 / 100	1164 ms	44876 KiB

race

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
// #include "temp.cpp"
#include <cstdio>
using namespace std;

#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif

#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());

#define pb push_back
#define popf pop_front
#define popb pop_back

void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}

template <class T> void print(set <T> v);
template <class T> void print(vector <T> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T, class V> void print(pair <T, V> p);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque<T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'

// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};

// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();

  if (str != "" && str != "input") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }

  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5 + 10;
int n, k, sz[N], compSize;
long long answ = -1;
vector<pair<int, long long>> adj[N], p;
bool used[N];
map<long long, long long> mp;

int dfs(int node, int parent) {
  sz[node] = 1; compSize++;
  for(auto i: adj[node]) {
    if(used[i.first] || i.first == parent) continue;
    sz[node] += dfs(i.first, node);
  }
  return sz[node];
}

int find_center(int node, int parent) {
  for(auto i: adj[node]) {
    if (used[i.first] || i.first == parent) continue;
    if (2 * sz[i.first] > compSize) {
      return find_center(i.first, node);
    }
  }
  return node;
}

int centroid(int u) {
  compSize = 0;
  dfs(u, 0);
  u = find_center(u, 0);
  return u;
}

void solve(int node, int parent, long long ln, int kn) {
  if(parent) {
    p.pb({kn, ln});
  }

  for(auto i: adj[node]) {
    if(i.first == parent || used[i.first]) continue;
    solve(i.first, node, ln + i.second, kn + 1);

    if(parent) continue;

    // exacly k -> Ln
    for(auto j: p) {
      long long Ln = j.second, Kn = j.first;
      if(Ln > k) continue;
      if(Ln == k) {
        if(answ == -1 || answ > Kn) {
          answ = Kn;
        }
      } else {
        auto it = mp.find(k - Ln);
        if(it != mp.end()) {
          if(answ == -1 || answ > Kn + it->second) {
            answ = Kn + it->second;
          }
        }
      }
    }

    for(auto j: p) {
      long long Ln = j.second, Kn = j.first;
      if(Ln > k) continue;

      auto it = mp.find(Ln);
      if(it == mp.end()) {
        mp[Ln] = Kn;
      } else {
        mp[Ln] = min(mp[Ln], Kn);
      }
    }
    p.clear();
  }
}

void centroid_decomposition() {
  queue<int> q;
  q.push(1);

  while(!q.empty()) {
    auto u = q.front();
    q.pop();

    int center = centroid(u);
    solve(center, 0, 0, 0);
    mp.clear();

    used[center] = true;
    for(auto i: adj[center]) {
      if(used[i.first]) continue;
      q.push(i.first);
    }
  }
}

int best_path(int M, int K, int H[][2], int L[]) {
  n = M, k = K;
  for(int i = 0; i < n - 1; i++) {
    int a = H[i][0], b = H[i][1], c = L[i]; a++, b++;
    adj[a].push_back({b, c});
    adj[b].push_back({a, c});
  }

  centroid_decomposition();

  return answ;
}

Compilation message (stderr)

race.cpp: In function 'void setIO(std::string)':
race.cpp:63:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:68:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:69:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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