Submission #736923

#	Time	Username	Problem	Language	Result	Execution time	Memory
736923		Sam_a17	Event Hopping 2 (JOI21_event2)	C++17	0 / 100	64 ms	35016 KiB

event2

#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 blt(x) __builtin_popcount(x)
 
#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, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
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 != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

int ka() {
	int x = 0;
	bool z = false;
	while (1)
	{
		char y = getchar();
		if (y == '-')
			z = true;
		else if ('0' <= y && y <= '9')
			x = x * 10 + y - '0';
		else
		{
			if (z)
				x *= -1;
			return x;
		}
	}
}

const int N = 1e5 + 10, M = 3005;
int nxt[N], n, m;
int dp[M][M];

vector<int> seq;

void go(int node) {
  seq.push_back(node);
  if(sz(seq) == m) {
    return;
  }
  if(nxt[node]) {
    go(nxt[node]);
  }
}

struct segTreeMin {
  vector<long long> mTree;
  int size;
 
  void init(long long n) {
    size = 1;
    while(size < n)  {
      size *= 2;
    }
    mTree.assign(2 * size - 1, INT64_MAX);
  }
 
  void upd(int u, long long v, int x, int lx, int rx) { // set value at pos u
    if(rx - lx == 1) {
      mTree[x] = v;
      return;
    }
 
    int m = (lx + rx) / 2;
    if(u < m) {
      upd(u, v, 2 * x + 1, lx, m);
    }else {
      upd(u, v, 2 * x + 2, m, rx);
    }
    mTree[x] = min(mTree[2 * x + 1], mTree[2 * x + 2]);
  }
 
  void upd(int u, long long v) {
    upd(u, v, 0, 0, size);
  }
 
  long long qry (int l, int r, int x, int lx, int rx) { // range queries
    if(l >= rx || lx >= r) {
      return INT64_MAX;
    }
    if(lx >= l && r >= rx) {
      return mTree[x];
    }
 
    int m = (rx + lx) / 2;
    long long s1 = qry(l, r, 2 * x + 1, lx, m);
    long long s2 = qry(l, r, 2 * x + 2, m, rx);
    return min(s1, s2);
  }
 
  long long qry(int l, int r) {
    return qry(l, r, 0, 0, size);
  }
};

segTreeMin seg_min;


void solve_() {
  cin >> n >> m;

  vector<pair<pair<int, int>, int>> vec;
  for(int i = 1; i <= n; i++) {
    int a, b; cin >> a >> b;
    vec.push_back({{a, b}, i});
    nxt[i - 1] = -1;
  }

  sort(all(vec));
  seg_min.init(n + 5);
  vector<int> where(n + 1);
  for(int j = 0; j < n; j++) {
    dp[j][1] = j;
    where[vec[j].second] = j;
    auto it = lower_bound(all(vec), make_pair(make_pair(vec[j].first.second, -1), -1));
    if(it == vec.end()) continue;
    nxt[j] = it - vec.begin();
  }

  for(int j = 2; j <= m; j++) {
    for(int i = 0; i < n; i++) {
      if(dp[i][j - 1] != -1) {
        seg_min.upd(i, vec[i].second);
      } else {
        seg_min.upd(i, INT64_MAX);
      }
    }

    for(int i = 0; i < n; i++) {
      if(nxt[i] == -1) {
        dp[i][j] = -1;
        continue;
      }
      long long ff = seg_min.qry(nxt[i], n);
      if(ff < n) {
        dp[i][j] = where[ff];
      } else {
        dp[i][j] = -1;
      }
    }
  }

  int min_ind = n + 1;
  for(int i = 0; i < n; i++) {
    if(dp[i][m] != -1) {
      min_ind = min(min_ind, vec[i].second);
    }
  }

  if(min_ind == n + 1) {
    cout << -1 << '\n';
  } else {
    vector<int> seq;

    min_ind = where[min_ind];
    for(int j = m; j >= 1; j--) {
      seq.push_back(vec[min_ind].second);
      min_ind = dp[min_ind][j];
    }

    sort(all(seq));

    for(auto i: seq) {
      cout << i << '\n';
    }
  }
} 
 
int main() {
  setIO();

  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

event2.cpp: In function 'void setIO(std::string)':
event2.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 + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
event2.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 1
• Subtask 3: 0 / 31
• Subtask 4: 0 / 61