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)
+    }
+}