Merge 623bdcb into 83ebc79

README.md

@@ -345,3 +345,4 @@ problems from
 * [Day 361](https://github.com/vaskoz/dailycodingproblem-go/issues/712)
 * [Day 362](https://github.com/vaskoz/dailycodingproblem-go/issues/714)
 * [Day 363](https://github.com/vaskoz/dailycodingproblem-go/issues/716)
+* [Day 364](https://github.com/vaskoz/dailycodingproblem-go/issues/718)

day364/problem.go

@@ -0,0 +1,38 @@
+package day364
+
+// LongestIncreasingSubsequence returns the longest increasing
+// subsequence.
+// Runs in O(N log N) time with O(N) extra space.
+func LongestIncreasingSubsequence(seq []int) []int {
+	p := make([]int, len(seq))
+	m := make([]int, len(seq)+1)
+	var l int
+	for i := range seq {
+		lo := 1
+		hi := l
+		for lo <= hi {
+			mid := (lo + hi) / 2
+			if (lo+hi)%2 != 0 {
+				mid++
+			}
+			if seq[m[mid]] <= seq[i] {
+				lo = mid + 1
+			} else {
+				hi = mid - 1
+			}
+		}
+		newL := lo
+		p[i] = m[newL-1]
+		m[newL] = i
+		if newL > l {
+			l = newL
+		}
+	}
+	s := make([]int, l)
+	k := m[l]
+	for i := len(s) - 1; i >= 0; i-- {
+		s[i] = seq[k]
+		k = p[k]
+	}
+	return s
+}

day364/problem_test.go

@@ -0,0 +1,31 @@
+package day364
+
+import (
+	"reflect"
+	"testing"
+)
+
+// nolint
+var testcases = []struct {
+	seq []int
+	lis []int
+}{
+	{[]int{0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15}, []int{0, 2, 6, 9, 11, 15}},
+}
+
+func TestLongestIncreasingSubsequence(t *testing.T) {
+	t.Parallel()
+	for _, tc := range testcases {
+		if result := LongestIncreasingSubsequence(tc.seq); !reflect.DeepEqual(result, tc.lis) {
+			t.Errorf("Expected %v, got %v", tc.lis, result)
+		}
+	}
+}
+
+func BenchmarkLongestIncreasingSubsequence(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			LongestIncreasingSubsequence(tc.seq)
+		}
+	}
+}