go: add «3110. Score of a String»

Signed-off-by: Matej Focko <me@mfocko.xyz>

go/score-of-a-string.go

@@ -0,0 +1,15 @@
+package score_of_a_string
+
+func scoreOfString(s string) int {
+	abs := func(x int) int {
+		return max(x, -x)
+	}
+
+	score := 0
+
+	for i := 0; i+1 < len(s); i++ {
+		score += abs(int(s[i]) - int(s[i+1]))
+	}
+
+	return score
+}