Submission #1257576

#	Time	Username	Problem	Language	Result	Execution time	Memory
1257576		madamadam3	Obstacles for a Llama (IOI25_obstacles)	C++20	0 / 100	2088 ms	12868 KiB

obstacles

#include "obstacles.h"
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using pi = pair<int, int>;

#define FOR(i, a, b) for (int i = a; i < b; i++)
#define ROF(i, a, b) for (int i = a; i >= b; i--)
#define each(a, x) for (auto &a : x)
#define all(x) (x).begin(), (x).end()
#define bg(x) (x).begin()
#define en(x) (x).end()
#define rev(x) reverse(all(x))
#define sz(x) int((x).size())
#define srt(x) sort(all(x))
#define cnt(a, x) count(all(x), a)
#define trace(x) each(a, (x)) cout << a << " "
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound

struct DSU {
  int n; vi par, siz;

  DSU() {};
  DSU(int N) {
    n = N; par.resize(n); siz.assign(n, 1);
    iota(all(par), 0);
  }

  int find(int v) {
    if (par[v] == v) return v;
    return par[v] = find(par[v]);
  }

  void unite(int a, int b) {
    a = find(a); b = find(b);
    if (a != b) {
      if (siz[a] < siz[b]) swap(a, b);
      par[b] = a;
      siz[a] += siz[b];
    }
  }
};

struct SegTree {
  int n; vector<int> arr, st;

  SegTree() {};
  SegTree(int N, vector<int> &Arr) {
    n = N; arr = Arr; st.assign(4*n, INT_MIN);
    build(0, 0, n);
  }

  int build(int i, int l, int r) {
    if (l + 1 == r) return st[i] = arr[l];

    int m = l + (r - l) / 2;
    return st[i] = max(build(2*i+1, l, m), build(2*i+2, m, r));
  }

  int query(int i, int l, int r, int ql, int qr) {
    if (r <= ql || qr <= l) return INT_MIN;
    if (ql <= l && r <= qr) return st[i];

    int m = l + (r - l) / 2;
    return max(query(2*i+1, l, m, ql, qr), query(2*i+2, m, r, ql, qr));
  }

  int query(int l, int r) {
    return query(0, 0, n, l, r);
  }
};

int n, m;
DSU dsu;
SegTree rows, cols;
vi t, h;
// vvi id;

void quadratic() {
  // id.assign(n, vi(m, -1));

  // dsu = DSU(n*m);
  dsu = DSU(m);
  int cd = 0;

  // FOR(i, 0, n) {
  //   FOR(j, 0, m) {
  //     id[i][j] = cd++;
  //   }
  // }

  // FOR(i, 0, n) {
    FOR(j, 0, m) {
      // if (T[i] <= h[j]) continue;
      if (t[n-1] <= h[j]) continue;

      // if (i > 0 && t[i-1] > h[j]) dsu.unite(id[i][j], id[i-1][j]);
      // if (j > 0 && t[i] > h[j-1]) dsu.unite(id[i][j], id[i][j-1]); 
      if (j > 0 && t[n-1] > h[j-1]) dsu.unite(j, j-1); 

      // if (i < n - 1 && t[i+1] > h[j]) dsu.unite(id[i][j], id[i+1][j]);
      // if (j < m - 1 && t[i] > h[j+1]) dsu.unite(id[i][j], id[i][j+1]); 
      if (j < m - 1 && t[n-1] > h[j+1]) dsu.unite(j, j+1); 
    }
  // }
}

void initialize(vi T, vi H) {
  t = T; h = H;
  n = sz(T), m = sz(H);
  // quadratic();
  rows = SegTree(n, T); cols = SegTree(m, H);
  
  return;
}

bool can_reach(int L, int R, int S, int D) {
  if (S > D) swap(S, D);
  int a = S, b = S;

  while (a > 0 && t[0] > h[a - 1]) a--;
  while (b < m - 1 && t[0] > h[b+1]) b++;

  int c = D, d = D;
  while (c > 0 && t[0] > h[c - 1]) c--;
  while (d < m- 1 && t[0] > h[d+1]) d++;

  if (b >= D) return true;

  int cl = a; for (int i = a; i <= b; i++) if (h[i] < h[cl]) cl = i;
  int cr = c; for (int i = c; i <= d; i++) if (h[i] < h[cr]) cr = i;

  int k = 0; for (; k < n; k++) if (k == n - 1 || t[k + 1] <= h[cl] || t[k+1] <= h[cr]) break;
  int br = rows.query(0, k+1);
  int bc = cols.query(cl, cr+1);

  return br > bc;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 13
• Subtask 4: 0 / 21
• Subtask 5: 0 / 25
• Subtask 6: 0 / 17