Create 0678-valid-parenthesis-string.go

Author: josuebrunel

go/0678-valid-parenthesis-string.go

@@ -0,0 +1,23 @@
+func checkValidString(s string) bool {
+	minLeft, maxLeft := 0, 0
+
+	for i := range s {
+		if s[i] == '(' {
+			minLeft++
+			maxLeft++
+		} else if s[i] == ')' {
+			minLeft--
+			maxLeft--
+		} else {
+			minLeft--
+			maxLeft++
+		}
+		if maxLeft < 0 {
+			return false
+		}
+		if minLeft < 0 {
+			minLeft = 0
+		}
+	}
+	return minLeft == 0
+}