题解 | #表示数字#

Swift题解：

while let s = readLine() {
    var t = ""
    let array = [Character](s)
    var prefix: Character? = nil
    for i in 0 ..< array.count {
        let c = array[i]
        if c.isNumber {
            if prefix == nil || !(prefix?.isNumber ?? false) {
                t.append("*")
            }
            t.append(c)
        } else {
            if let p = prefix, p.isNumber {
                t.append("*")
            }
            t.append(c)
        }
        prefix = c
    }
    if let p = prefix, p.isNumber {
        t.append("*")
    }
    print(t)
}