719

Author: baishuai

algorithms/p719/719.go

@@ -0,0 +1,35 @@
+package p719
+
+import (
+	"sort"
+)
+
+func countDistance(nums []int, d int) int {
+	//slide window
+	l, r := 0, 0
+	cnt := 0
+	for r < len(nums) {
+		for r < len(nums) && nums[r]-nums[l] <= d {
+			cnt += r - l
+			r++
+		}
+		if r < len(nums) {
+			for nums[r]-nums[l] > d {
+				l++
+			}
+		}
+	}
+	return cnt
+}
+
+func smallestDistancePair(nums []int, k int) int {
+	sort.Ints(nums)
+	if len(nums) <= 1 {
+		return 0
+	}
+	n := nums[len(nums)-1] - nums[0]
+	v := sort.Search(n, func(i int) bool {
+		return countDistance(nums, i) >= k
+	})
+	return v
+}

algorithms/p719/719_test.go

@@ -0,0 +1,18 @@
+package p719
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test0(t *testing.T) {
+
+	nums := []int{1, 3, 1}
+	assert.Equal(t, 0, smallestDistancePair(nums, 1))
+}
+
+func TestCount(t *testing.T) {
+	nums := []int{1, 2, 3, 4, 5}
+	assert.Equal(t, 7, countDistance(nums, 2))
+}