# ADD - contiguous subarray sum

src/contiguous_subarray_sum.go

@@ -0,0 +1,24 @@
+// Given an array of numbers, return true if there is a contiguous subarray that sums up to a certain number n.
+
+// const arr = [1, 2, 3], sum = 5
+// subarraySum(arr, sum)
+// // true
+
+// const arr = [11, 21, 4], sum = 9
+// subarraySum(arr, sum)
+// // false
+// In the above examples, 2, 3 sum up to 5 so we return true. On the other hand, no subarray in [11, 21, 4] can sum up to 9.
+
+// solution: https://algodaily.com/challenges/contiguous-subarray-sum
+
+package main
+
+func subarraySum(arr []int, sum int) bool {
+	for i, v := range arr {
+		if i+1 < len(arr) && v+arr[i+1] == sum {
+			return true
+		}
+	}
+
+	return false
+}

src/contiguous_subarray_sum_test.go

@@ -0,0 +1,38 @@
+package main
+
+import "testing"
+
+func Test_subarraySum(t *testing.T) {
+	type args struct {
+		arr []int
+		sum int
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			"`sum` number exists",
+			args{[]int{1, 2, 3}, 5},
+			true,
+		},
+		{
+			"`sum` number exists",
+			args{[]int{1, 2, 3}, 3},
+			true,
+		},
+		{
+			"`sum` number does not exists",
+			args{[]int{11, 21, 4}, 5},
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := subarraySum(tt.args.arr, tt.args.sum); got != tt.want {
+				t.Errorf("subarraySum() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}