#include "walk.h"
#include <bits/stdc++.h>
using namespace std;
int dist (array<int, 2> &a, array<int, 2> &b) {
return abs(a[0] - b[0]) + abs(a[1] - b[1]);
}
long long min_distance(std::vector<int> x, std::vector<int> h, std::vector<int> l, std::vector<int> r, std::vector<int> y, int src, int snk) {
vector<array<int, 2>> p;
int n = x.size(), m = y.size();
vector<vector<int>> seg(n + m), adj((int)1e6);
auto add = [&] (int i) {
adj[p.size()].push_back(i);
seg[i].push_back(p.size());
};
for (int i = 0; i < n; ++i) {
add(i);
p.push_back({x[i], 0});
add(i);
p.push_back({x[i], h[i]});
}
for (int i = 0; i < m; ++i) {
add(l[i]);
add(n + i);
p.push_back({x[l[i]], y[i]});
add(r[i]);
add(n + i);
p.push_back({x[r[i]], y[i]});
for (int j = l[i]; j <= r[i]; ++j) {
if (h[j] >= y[i]) {
add(j);
add(n + i);
p.push_back({x[j], y[i]});
}
}
}
priority_queue<pair<long long, int>> pq;
pq.push({0, 2 * src});
vector<long long> dis(adj.size(), 1e18);
dis[2 * src] = 0;
while (pq.size()) {
long long d = -pq.top().first;
int u = pq.top().second;
pq.pop();
if (d != dis[u]) {
continue;
}
for (int e : adj[u]) {
for (int v : seg[e]) {
int dd = dist(p[u], p[v]);
if (d + dd < dis[v]) {
dis[v] = d + dd;
pq.push({-dis[v], v});
}
}
}
}
return dis[2 * snk] == 1e18 ? -1 : dis[2 * snk];
}
