Problem p02347 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;
class Node {
public:
  int location;
  int p, l, r;
  Node() {}
};
class Point {
public:
  int id, x, y;
  Point() {}
  Point(int id, int x, int y) : id(id), x(x), y(y) {}
  bool operator<(const Point &p) { return id < p.id; }
};
static const int MAX = 1000000;
static const int NIL = -1;
int n;
Point P[MAX];
Node T[MAX];
int np;
bool lessX(const Point &p1, const Point &p2) { return p1.x < p2.x; }
bool lessY(const Point &p1, const Point &p2) { return p1.y < p2.y; }
int makeKDTree(int l, int r, int d) {
  if (!(l < r))
    return NIL;
  int mid = (l + r) / 2;
  int t = np++;
  if (d % 2 == 0)
    sort(P + l, P + r, lessX);
  else
    sort(P + l, P + r, lessY);
  T[t].location = mid;
  T[t].l = makeKDTree(l, mid, d + 1);
  T[t].r = makeKDTree(mid + 1, r, d + 1);
  return t;
}
void find(int v, int sx, int tx, int sy, int ty, int d, vector<Point> &ans) {
  int x = P[T[v].location].x;
  int y = P[T[v].location].y;
  if (sx <= x && x <= tx && sy <= y && y <= ty)
    ans.push_back(P[T[v].location]);
  if (d % 2 == 0) {
    if (T[v].l != NIL)
      if (sx <= x)
        find(T[v].l, sx, tx, sy, ty, d + 1, ans);
    if (T[v].r != NIL)
      if (x <= tx)
        find(T[v].r, sx, tx, sy, ty, d + 1, ans);
  } else {
    if (T[v].l != NIL)
      if (sy <= y)
        find(T[v].l, sx, tx, sy, ty, d + 1, ans);
    if (T[v].r != NIL)
      if (y <= ty)
        find(T[v].r, sx, tx, sy, ty, d + 1, ans);
  }
}
int main() {
  int x, y;
  cin >> n;
  rep(i, n) {
    scanf("%d %d", &x, &y);
    P[i] = Point(i, x, y);
    T[i].l = T[i].r = T[i].p = NIL;
  }
  np = 0;
  int root = makeKDTree(0, n, 0);
  int q;
  cin >> q;
  int sx, sy, tx, ty;
  vector<Point> ans;
  rep(i, q) {
    scanf("%d %d %d %d", &sx, &tx, &sy, &ty);
    ans.clear();
    find(root, sx, tx, sy, ty, 0, ans);
    sort(ans.begin(), ans.end());
    rep(j, ans.size()) printf("%d\\n", ans[j].id);
    cout << endl;
  }
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;

class Node {
public:
  int location;
  int p, l, r;
  Node() {}
};

class Point {
public:
  int id, x, y;
  Point() {}
  Point(int id, int x, int y) : id(id), x(x), y(y) {}
  bool operator<(const Point &p) { return id < p.id; }
};

static const int MAX = 100000;
static const int NIL = -1;

int n;
Point P[MAX];
Node T[MAX];

int np;

bool lessX(const Point &p1, const Point &p2) { return p1.x < p2.x; }
bool lessY(const Point &p1, const Point &p2) { return p1.y < p2.y; }

int makeKDTree(int l, int r, int d) {
  if (!(l < r))
    return NIL;
  int mid = (l + r) >> 1;
  int t = np++;
  nth_element(P + l, P + mid, P + r, (d & 1 ? lessY : lessX));
  T[t].location = mid;
  T[t].l = makeKDTree(l, mid, d + 1);
  T[t].r = makeKDTree(mid + 1, r, d + 1);
  return t;
}

void find(int v, int sx, int tx, int sy, int ty, int d, vector<Point> &ans) {
  int x = P[T[v].location].x;
  int y = P[T[v].location].y;
  if (sx <= x && x <= tx && sy <= y && y <= ty)
    ans.push_back(P[T[v].location]);
  // int res=-1;
  if (d % 2 == 0) {
    if (T[v].l != NIL && sx <= x)
      find(T[v].l, sx, tx, sy, ty, d + 1, ans);
    // if(res!=-1)return res;
    if (T[v].r != NIL && x <= tx)
      find(T[v].r, sx, tx, sy, ty, d + 1, ans);
  } else {
    if (T[v].l != NIL && sy <= y)
      find(T[v].l, sx, tx, sy, ty, d + 1, ans);
    // if(res!=-1)return res;
    if (T[v].r != NIL && y <= ty)
      find(T[v].r, sx, tx, sy, ty, d + 1, ans);
  }
  // return res;
}

bool exist(int v, int sx, int tx, int sy, int ty, int d, vector<Point> &ans) {
  int x = P[T[v].location].x;
  int y = P[T[v].location].y;
  if (sx <= x && x <= tx && sy <= y && y <= ty)
    ans.push_back(P[T[v].location]);

  if (d % 2 == 0) {
    if (T[v].l != NIL && sx <= x)
      if (exist(T[v].l, sx, tx, sy, ty, d + 1, ans))
        return 1;
    if (T[v].r != NIL && x <= tx)
      if (exist(T[v].r, sx, tx, sy, ty, d + 1, ans))
        return 1;
  } else {
    if (T[v].l != NIL && sy <= y)
      if (exist(T[v].l, sx, tx, sy, ty, d + 1, ans))
        return 1;
    if (T[v].r != NIL && y <= ty)
      if (exist(T[v].r, sx, tx, sy, ty, d + 1, ans))
        return 1;
  }
  return 0;
}

int main() {
  int x, y;
  cin >> n;
  rep(i, n) {
    scanf("%d %d", &x, &y);
    P[i] = Point(i, x, y);
    T[i].l = T[i].r = T[i].p = NIL;
  }
  np = 0;
  int root = makeKDTree(0, n, 0);
  int q;
  cin >> q;
  int sx, sy, tx, ty;
  vector<Point> ans;
  rep(i, q) {
    scanf("%d %d %d %d", &sx, &tx, &sy, &ty);
    ans.clear();
    find(root, sx, tx, sy, ty, 0, ans);
    sort(ans.begin(), ans.end());
    rep(j, ans.size()) printf("%d\\n", ans[j].id);
    cout << endl;
  }
  return 0;
}