20201224

20201224/main.go

@@ -0,0 +1,37 @@
+package main
+
+func main() {
+
+}
+
+func isEcho(s string) bool {
+	var sc []uint8
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if isAlphabetAndDigit(c) {
+			if c <= 'Z' && c >= 'A' {
+				c += 'a' - 'A'
+			}
+			sc = append(sc, c)
+		}
+	}
+	if len(sc) == 0 {
+		return true
+	}
+	l, r := 0, len(sc)-1
+	for {
+		if l >= r {
+			break
+		}
+		if sc[l] != sc[r] {
+			return false
+		}
+		l++
+		r--
+	}
+	return true
+}
+
+func isAlphabetAndDigit(c uint8) bool {
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')
+}