#include "obstacles.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using pi = pair<int, int>;
struct SegTree {
int n; vi arr; vector<pi> st;
SegTree() {}
SegTree(int N, vi &Arr) {
n = N; arr = Arr; st.assign(4*n, {-1, -1});
build(0, 0, n);
}
pi combine(pi x, pi y) {
pi r = {-1, -1};
if (x.first < 0) r.first = y.first;
else if (y.first < 0) r.first = x.first;
else r.first = arr[x.first] < arr[y.first] ? x.first : y.first;
if (x.second < 0) r.second = y.second;
else if (y.second < 0) r.second = x.second;
else r.second = arr[x.second] > arr[y.second] ? x.second : y.second;
return r;
}
pi build(int i, int l, int r) {
if (l+1==r) return st[i] = {l, l};
int m = l + (r- l)/2;
return st[i] = combine(build(2*i+1, l, m), build(2*i+2, m, r));
}
pi query(int i, int l, int r, int ql, int qr) {
if (qr <= l || r <= ql) return {-1, -1};
if (ql <= l && r <= qr) return st[i];
int m = l + (r - l) / 2;
return combine(query(2*i+1, l, m, ql, qr), query(2*i+2, m, r, ql, qr));
}
};
int r, c;
SegTree row, col;
vi t, h;
void initialize(vi T, vi H) {
r = T.size(); c = H.size();
t = T; h = H;
row = SegTree(r, T); col = SegTree(c, H);
return;
}
bool can_reach(int L, int R, int s, int d) {
if (s>d) swap(s, d);
int mx = h[col.query(0, 0, c, s, d+1).second];
int lo = 0, hi = r;
while (lo < hi) {
int mid = lo + (hi - lo) / 2;
if (t[row.query(0, 0, r, 0, mid+1).second] > mx) hi = mid;
else lo = mid + 1;
}
int first = lo;
if (first >= r || t[first] <= mx) return false;
auto get_range = [&](int i, int x, int ca, int cb) {
// int lo1 = 0, hi1 = x;
// int lo2 = x, hi2 = c;
// while (lo1 < hi1) {
// int mid = lo1 + (hi1 - lo1) / 2;
// if (h[col.query(0, 0, c, mid, x+1).second] < t[i]) hi1 = mid;
// else lo1 = mid + 1;
// }
// while (lo2 < hi2) {
// int mid = lo2 + (hi2 - lo2) / 2;
// if (h[col.query(0, 0, c, x, mid+1).second] < t[i]) lo2 = mid+1;
// else hi2 = mid;
// }
// return make_pair(lo1, lo2-1);
int a = ca, b = cb;
while (a > 0 && t[i] > h[a-1]) a--;
while (b < c-1 && t[i] > h[b+1]) b++;
return make_pair(a, b);
};
int ra = 0, rb = 0;
int ca = s, cb = s, da = d, db = d;
while (ra < first || rb < first) {
if (ra < first) {
auto range = get_range(ra, s, ca, cb);
ca = range.first, cb = range.second;
int best = col.query(0, 0, c, range.first, range.second+1).first;
if (t[ra+1] <= h[best]) return false;
ra++; s = best;
}
if (rb < first) {
auto range = get_range(rb, d, da, db);
da = range.first, db = range.second;
int best = col.query(0, 0, c, range.first, range.second+1).first;
if (t[rb+1] <= h[best]) return false;
rb++; d = best;
}
}
return true;
}
