Which depot is closest
A last-mile sheet lists every depot as an x, y position on a grid. Pick the depot nearest a delivery point, Manhattan distance.
- Distance is |x1 - x2| + |y1 - y2|, in whole units.
- A tie is broken by whoever comes first in the list.
- With no depots at all return -1.
nearestDepot(depots: list<Point>, x: int, y: int) → int
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
int nearestDepot(List<Point> depots, int x, int y) {
}Worked examples
| Call | Result |
|---|---|
nearestDepot(Main.<Point>ls(new Point(0, 0), new Point(10, 0), new Point(3, 4)), 4, 4) | 2 |
nearestDepot(Main.<Point>ls(new Point(0, 0), new Point(2, 2)), 1, 1) | 0 |
nearestDepot(Main.<Point>ls(new Point(9, 9)), 0, 0) | 0 |
nearestDepot(Main.<Point>ls(), 0, 0) | -1 |
Hint
Track a best index while you walk the list.
Reference solution in Java
int nearestDepot(List<Point> depots, int x, int y) {
int best = -1, bestDist = Integer.MAX_VALUE;
for (int i = 0; i < depots.size(); i++) {
Point p = depots.get(i);
int d = Math.abs(p.x - x) + Math.abs(p.y - y);
if (d < bestDist) { bestDist = d; best = i; }
}
return best;
}