Add tapeequilibrium solution, unit test and benchmark

tapeequilibrium.go

@@ -0,0 +1,26 @@
+package goexercises
+
+import "math"
+
+// TapeEquilibrium - https://codility.com/programmers/lessons/3-time_complexity/tape_equilibrium/
+// Minimize the value `|(A[0] + ... + A[P-1]) - (A[P] + ... + A[N-1])|`
+func TapeEquilibrium(slice []int) int {
+	total := sumSliceInt(slice)
+	min, leftSide := math.MaxFloat64, 0
+	for _, v := range slice {
+		rightSide := total - v - leftSide
+		leftSide += v
+		difference := math.Abs(float64(rightSide - leftSide))
+		if difference < min {
+			min = difference
+		}
+	}
+	return int(min)
+}
+
+func sumSliceInt(slice []int) (sum int) {
+	for _, v := range slice {
+		sum += v
+	}
+	return
+}

tapeequilibrium_test.go

@@ -0,0 +1,56 @@
+package goexercises
+
+import "testing"
+
+func TestTapeEquilibrium(t *testing.T) {
+	testCases := []struct {
+		slice    []int
+		expected int
+	}{
+		{[]int{3, 1, 2, 4, 3}, 1},
+		{[]int{3, 1, 2, 4, 3, 1, 2, 3, 10}, 1},
+		{[]int{2, 3, 10}, 5},
+		{[]int{0}, 0},
+		{[]int{0, 1}, 1},
+	}
+	for _, test := range testCases {
+		observed := TapeEquilibrium(test.slice)
+		if observed != test.expected {
+			t.Errorf("for slice '%v', expected '%d', observed '%d'\n",
+				test.slice, test.expected, observed)
+		}
+	}
+}
+
+func BenchmarkTapeEquilibrium(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		TapeEquilibrium([]int{0, 1, 2, 3, 4, 5})
+	}
+}
+
+func TestSumSliceInt(t *testing.T) {
+	testCases := []struct {
+		slice    []int
+		expected int
+	}{
+		{[]int{1, 1, 1}, 3},
+		{[]int{0}, 0},
+		{[]int{1}, 1},
+		{[]int{1, 3}, 4},
+		{[]int{1, -1}, 0},
+		{[]int{-1, -1}, -2},
+	}
+	for _, test := range testCases {
+		observed := sumSliceInt(test.slice)
+		if observed != test.expected {
+			t.Errorf("for slice '%v', expected '%d', observed '%d'\n",
+				test.slice, test.expected, observed)
+		}
+	}
+}
+
+func BenchmarkSumSliceInt(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		sumSliceInt([]int{0, 1, 2, 3, 4, 5})
+	}
+}