Add: Sqrt(x)

Author: openset

problems/sqrtx/sqrtx.go

@@ -1 +1,12 @@
 package sqrtx
+
+func mySqrt(x int) int {
+	if x < 2 {
+		return x
+	}
+	r := x / 2
+	for r > x/r {
+		r = (r + x/r) / 2
+	}
+	return r
+}

problems/sqrtx/sqrtx_test.go

@@ -1 +1,35 @@
 package sqrtx
+
+import "testing"
+
+type caseType struct {
+	input    int
+	expected int
+}
+
+func TestMySqrt(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    4,
+			expected: 2,
+		},
+		{
+			input:    8,
+			expected: 2,
+		},
+		{
+			input:    0,
+			expected: 0,
+		},
+		{
+			input:    1,
+			expected: 1,
+		},
+	}
+	for _, tc := range tests {
+		output := mySqrt(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}