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

#include <algorithm>
#include <cstdio>
#include <vector>

using namespace std;

class Node {
public:
  int location;
  int parent;
  int right;
  int left;

  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) const { return id < p.id; }

  void print() { printf("%d\\n", 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 left, int right, int depth) {
  if (!(left < right)) {
    return NIL;
  }
  int mid = (left + right) / 2;
  int t = np++;
  if (depth % 2 == 0) {
    sort(P + left, P + right, lessX);
  } else {
    sort(P + left, P + right, lessY);
  }
  T[t].location = mid;
  T[t].left = makeKDTree(left, mid, depth + 1);
  T[t].right = makeKDTree(mid + 1, right, depth + 1);

  return t;
}

void find(int v, int sx, int tx, int sy, int ty, int depth,
          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 (depth % 2 == 0) {
    if (T[v].left != NIL) {
      if (sx <= x) {
        find(T[v].left, sx, tx, sy, ty, depth + 1, ans);
      }
    }
    if (T[v].right != NIL) {
      if (x <= tx) {
        find(T[v].right, sx, tx, sy, ty, depth + 1, ans);
      }
    }
  } else {
    if (T[v].left != NIL) {
      if (sy <= y) {
        find(T[v].left, sx, tx, sy, ty, depth + 1, ans);
      }
    }
    if (T[v].right != NIL) {
      if (y <= ty) {
        find(T[v].right, sx, tx, sy, ty, depth + 1, ans);
      }
    }
  }
}

int main() {
  int x, y;
  scanf("%d", &N);
  for (int i = 0; i < N; i++) {
    scanf("%d %d", &x, &y);
    P[i] = Point(i, x, y);
    T[i].left = T[i].right = T[i].parent = NIL;
  }

  np = 0;

  int root = makeKDTree(0, N, 0);

  int q;
  scanf("%d", &q);
  int sx, tx, sy, ty;
  vector<Point> ans;
  for (int i = 0; i < q; i++) {
    scanf("%d %d %d %d", &sx, &tx, &sy, &ty);
    ans.clear();
    find(root, sx, tx, sy, ty, 0, ans);
    sort(ans.begin(), ans.end());
    for (int j = 0; j < ans.size(); j++) {
      ans[j].print();
    }
    printf("\\n");
  }

  return 0;
}


Error: TLE

Fixed submission:

#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

class Node {
public:
  int location;
  int parent;
  int right;
  int left;

  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) const { return id < p.id; }

  void print() { cout << id << endl; }
};

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 left, int right, int depth) {
  if (!(left < right)) {
    return NIL;
  }
  int mid = (left + right) / 2;
  int t = np++;
  if (depth % 2 == 0) {
    sort(P + left, P + right, lessX);
  } else {
    sort(P + left, P + right, lessY);
  }
  T[t].location = mid;
  T[t].left = makeKDTree(left, mid, depth + 1);
  T[t].right = makeKDTree(mid + 1, right, depth + 1);

  return t;
}

void find(int v, int sx, int tx, int sy, int ty, int depth,
          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 (depth % 2 == 0) {
    if (T[v].left != NIL) {
      if (sx <= x) {
        find(T[v].left, sx, tx, sy, ty, depth + 1, ans);
      }
    }
    if (T[v].right != NIL) {
      if (x <= tx) {
        find(T[v].right, sx, tx, sy, ty, depth + 1, ans);
      }
    }
  } else {
    if (T[v].left != NIL) {
      if (sy <= y) {
        find(T[v].left, sx, tx, sy, ty, depth + 1, ans);
      }
    }
    if (T[v].right != NIL) {
      if (y <= ty) {
        find(T[v].right, sx, tx, sy, ty, depth + 1, ans);
      }
    }
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int x, y;
  cin >> N;
  for (int i = 0; i < N; i++) {
    cin >> x >> y;
    P[i] = Point(i, x, y);
    T[i].left = T[i].right = T[i].parent = NIL;
  }

  np = 0;

  int root = makeKDTree(0, N, 0);

  int q;
  cin >> q;
  int sx, tx, sy, ty;
  vector<Point> ans;
  for (int i = 0; i < q; i++) {
    cin >> sx >> tx >> sy >> ty;
    ans.clear();
    find(root, sx, tx, sy, ty, 0, ans);
    sort(ans.begin(), ans.end());
    for (int j = 0; j < ans.size(); j++) {
      ans[j].print();
    }
    cout << endl;
  }

  return 0;
}