Create 0973-k-closest-points-to-origin.go

go/0973-k-closest-points-to-origin.go

@@ -0,0 +1,55 @@
+type PointEntry struct {
+ dist int
+ x int
+ y int
+}
+
+type PointHeap []*PointEntry
+
+func (h PointHeap) Len() int { return len(h) }
+func (h PointHeap) Less(i, j int) bool { return h[i].dist < h[j].dist }
+func (h PointHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
+func (h *PointHeap) Push(x interface{}) {*h = append(*h, x.(*PointEntry))}
+func (h *PointHeap) Pop() interface{} {
+ old := *h
+ n := len(old)
+ x := old[n-1]
+ *h = old[0 : n-1]
+ return x
+}
+
+const X = 0
+const Y = 1
+func kClosest(points [][]int, k int) [][]int {
+ _pts := make([]*PointEntry, 0, len(points))
+ for _, point := range points {
+ dist := (pow(abs(point[X] - 0), 2) + pow(abs(point[Y] - 0), 2))
+ _pts = append(_pts, &PointEntry{dist: dist, x: point[X], y: point[Y]})
+ }
+ pts := PointHeap(_pts)
+
+ res := make([][]int, 0)
+ heap.Init(&pts)
+ for i := 0; i < k; i++ {
+ pointEntry := heap.Pop(&pts).(*PointEntry)
+ res = append(res, []int{pointEntry.x, pointEntry.y})
+ }
+ return res
+}
+
+func abs(a int) int {
+ if a < 0 {
+ return -a
+ }
+ return a
+}
+
+func pow(x, n int) int {
+ if n == 0 {
+ return 1
+ } else if n == 1 {
+ return x
+ } else {
+ return pow(x, n/2) * pow(x, (n + 1)/2)
+ }
+}