#include "jumps.h"
#include <bits/stdc++.h>
#include <vector>
using namespace std;
const int MAXN = 2e5 + 5;
int dp_min[19][MAXN], dp_max[19][MAXN];
vector<int> seg[MAXN * 4]; // at position i stores the value H[i]
vector<int> H, REV;
int N;
void Build(int left, int right, int pos)
{
if(left == right)
{
seg[pos].push_back(H[left]);
return;
}
int mid = (left + right) / 2;
Build(left, mid, pos * 2);
Build(mid + 1, right, pos * 2 + 1);
merge(seg[pos * 2].begin(), seg[pos * 2].end(), seg[pos * 2 + 1].begin(), seg[pos * 2 + 1].end(), back_inserter(seg[pos]));
}
int Query(int l, int r, int pos, int ql, int qr, int qval)
{
// cout << "qpos = " << ql << ", " << qr << ", qval = " << qval << "\n";
if(ql > r || l > qr)
{
return -1;
}
if(ql <= l && r <= qr)
{
int cur_pos = lower_bound(seg[pos].begin(), seg[pos].end(), qval) - seg[pos].begin() - 1;
if(cur_pos == -1)
{
return -1;
}
return seg[pos][cur_pos];
}
int mid = (l + r) >> 1;
return max(Query(l, mid, pos * 2, ql, qr, qval), Query(mid + 1, r, pos * 2 + 1, ql, qr, qval));
}
void init(int n, std::vector<int> h)
{
stack<int> s;
N = n;
REV.resize(N + 1);
for(int i = 0; i < h.size(); i++)
{
H.push_back(h[i]);
REV[H[i]] = i;
}
Build(0, N - 1, 1);
for(int i = 0; i < N; i++)
{
while(!s.empty() && H[s.top()] < H[i])
{
s.pop();
}
if(s.empty())
{
dp_min[0][i] = -1;
}
else
{
dp_min[0][i] = s.top();
}
s.push(i);
}
while(!s.empty())
{
s.pop();
}
for(int i = N - 1; i >= 0; i--)
{
while(!s.empty() && H[s.top()] < H[i])
{
s.pop();
}
if(s.empty())
{
dp_max[0][i] = -1;
}
else
{
dp_max[0][i] = s.top();
}
s.push(i);
if(dp_min[0][i] == -1 || (dp_max[0][i] != -1 && H[dp_max[0][i]] < H[dp_min[0][i]]))
{
swap(dp_min[0][i], dp_max[0][i]);
}
}
for(int i = 1; i < 19; i++)
{
for(int j = 0; j < N; j++)
{
dp_min[i][j] = (dp_min[i - 1][j] == -1) ? -1 : dp_min[i - 1][dp_min[i - 1][j]];
dp_max[i][j] = (dp_max[i - 1][j] == -1) ? -1 : dp_max[i - 1][dp_max[i - 1][j]];
assert(dp_max[i][j] == -1 || H[dp_max[i][j]] >= H[dp_min[i][j]]);
}
}
}
int minimum_jumps(int A, int B, int C, int D)
{
// A = B && C = D
// cout << "---- ---- ---- ---- ----\n";
// cout << "A = " << A << ", B = " << B << "\n";
int query_result = Query(0, N - 1, 1, A, B, H[C]);
// cout << "query_result = " << query_result << "\n";
if(query_result == -1)
{
return -1;
}
A = REV[query_result];
B = A;
// cout << "A = " << A << ", B = " << B << "\n";
// cout << "---- ---- ---- ---- ----\n";
int ans = 0;
for(int i = 18; i >= 0; i--)
{
if(dp_max[i][A] != -1 && H[dp_max[i][A]] <= H[C])
{
ans += (1 << i);
A = dp_max[i][A];
}
}
for(int i = 18; i >= 0; i--)
{
if(dp_min[i][A] != -1 && H[dp_min[i][A]] <= H[C])
{
ans += (1 << i);
A = dp_min[i][A];
}
}
if(H[A] != H[C])
{
return -1;
}
return ans;
}
