Binary Search

slice_searching/binary_search/binary_search.go

@@ -0,0 +1,21 @@
+package binarysearch
+
+// Runs a binary search on a given slice numerical values
+func BinarySearch(param int, slice []int) int {
+	low := 0
+	high := len(slice) - 1
+	mid := low + (high-low)/2
+
+	for {
+		if mid > len(slice)-1 || mid < 0 {
+			return -1
+		} else if slice[mid] > param {
+			mid -= 1
+		} else if slice[mid] < param {
+			mid += 1
+		} else {
+			return mid
+		}
+	}
+
+}

slice_searching/binary_search/binary_search_test.go

@@ -0,0 +1,47 @@
+package binarysearch
+
+import "testing"
+
+func TestBinarySearch(t *testing.T) {
+	type args struct {
+		param int
+		slice []int
+	}
+	tests := []struct {
+		name string
+		args args
+		want int
+	}{
+		{
+			name: "it correctly finds the expected index",
+			args: args{
+				param: 4,
+				slice: []int{6, 8, 2, 4, 6},
+			},
+			want: 3,
+		},
+		{
+			name: "it returns -1 when out of bounds > length",
+			args: args{
+				param: 10,
+				slice: []int{6, 8, 2, 4, 6},
+			},
+			want: -1,
+		},
+		{
+			name: "it returns -1 when mid < 0",
+			args: args{
+				param: -1,
+				slice: []int{6, 8, 2, 4, 6},
+			},
+			want: -1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := BinarySearch(tt.args.param, tt.args.slice); got != tt.want {
+				t.Errorf("BinarySearch() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}