feat: solution: easy: adjacent-increasing-subarrays-detection-i.go

Author: illiafox

src/easy/adjacent-increasing-subarrays-detection-i.go

@@ -0,0 +1,27 @@
+package easy
+
+// https://leetcode.com/problems/adjacent-increasing-subarrays-detection-i
+func hasIncreasingSubarrays(nums []int, k int) bool {
+	n := len(nums)
+	if k <= 0 || 2*k > n {
+		return false
+	}
+
+	increment := make([]int, n)
+	increment[n-1] = 1
+	for i := n - 2; i >= 0; i-- {
+		if nums[i] < nums[i+1] {
+			increment[i] = increment[i+1] + 1
+		} else {
+			increment[i] = 1
+		}
+	}
+
+	for i := 0; i <= n-2*k; i++ {
+		if increment[i] >= k && increment[i+k] >= k {
+			return true
+		}
+	}
+
+	return false
+}

src/easy/adjacent-increasing-subarrays-detection-i_test.go

@@ -0,0 +1,74 @@
+package easy
+
+import "testing"
+
+func TestHasIncreasingSubarrays(t *testing.T) {
+	cases := []struct {
+		nums []int
+		k    int
+		want bool
+	}{
+		{
+			nums: []int{1, 2, 3, 4, 5, 6},
+			k:    3,
+			// [1,2,3] and [4,5,6] are both strictly increasing
+			want: true,
+		},
+		{
+			nums: []int{10, 0},
+			k:    1,
+			// two adjacent singletons -> trivially true
+			want: true,
+		},
+		{
+			nums: []int{1, 2, 3},
+			k:    2,
+			// need 4 elements for two adjacent length-2 windows
+			want: false,
+		},
+		{
+			nums: []int{1, 2, 3, 4},
+			k:    0,
+			want: false,
+		},
+		{
+			nums: []int{1, 2, 2, 3, 4, 5},
+			k:    2,
+			// possible windows starting at 3: [3,4] and [4,5] => true
+			want: true,
+		},
+		{
+			nums: []int{1, 2, 3, 4},
+			k:    2,
+			// [1,2] and [3,4] -> both increasing
+			want: true,
+		},
+		{
+			nums: []int{2, 5, 7, 8, 9, 2, 3, 4, 3, 1},
+			k:    3,
+			want: true,
+		},
+		{
+			nums: []int{1, 2, 3, 4, 4, 4, 4, 5, 6, 7},
+			k:    5,
+			want: false,
+		},
+		{
+			nums: []int{-15, 19},
+			k:    1,
+			want: true,
+		},
+		{
+			nums: []int{5, 8, -2, -1},
+			k:    2,
+			want: true,
+		},
+	}
+
+	for _, tc := range cases {
+		got := hasIncreasingSubarrays(tc.nums, tc.k)
+		if got != tc.want {
+			t.Fatalf("hasIncreasingSubarrays(%v, %d) = %v, want %v", tc.nums, tc.k, got, tc.want)
+		}
+	}
+}