#include <vector>
#include <algorithm>
// Provided by the grader — DO NOT implement yourself!
int use_detector(int x);
// You must implement this
std::vector<int> find_routers(int l, int n, int q) {
std::vector<int> positions(n);
positions[0] = 0; // router 0 is always at position 0
for (int i = 1; i < n; ++i) {
// Binary search: leftmost position where use_detector(x) == i
int lo = 0, hi = l, left = -1;
while (lo <= hi) {
int mid = (lo + hi) / 2;
int res = use_detector(mid);
if (res < i) {
lo = mid + 1;
} else {
if (res == i) left = mid;
hi = mid - 1;
}
}
// Binary search: rightmost position where use_detector(x) == i
lo = 0, hi = l;
int right = -1;
while (lo <= hi) {
int mid = (lo + hi) / 2;
int res = use_detector(mid);
if (res > i) {
hi = mid - 1;
} else {
if (res == i) right = mid;
lo = mid + 1;
}
}
// Estimate router position as the center of its range, rounded down to even
int pos = ((left + right) / 2) & ~1;
positions[i] = pos;
}
return positions;
}
