1576. 替换所有的问号

题目链接：https://leetcode-cn.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters

执行用时：0 ms, 在所有 Swift 提交中击败了100.00%的用户
内存消耗：13.3 MB, 在所有 Swift 提交中击败了100.00%的用户

class Solution {
    func modifyString(_ s: String) -> String {
        var arr = Array(s)
        let len = arr.count
        var ch:Character = "a"
        for i in 0 ..< len {
            if arr[i] == "?" {
                let aValue = Int(("a" as UnicodeScalar).value)
                var count = 0
                // 与两边字符比较是否相等
                while (i > 0 && arr[i-1] == ch) ||
                        (i < len-1 && arr[i+1] == ch) {
                            // ascii码转换
                    ch = Character(UnicodeScalar(count + aValue)!)
                    count += 1
                }
                arr[i] = ch
            }
        }
        return String(arr)
    }
}

java代码，来自题解

class Solution {
    public String modifyString(String s) {
        char[] ss = s.toCharArray();
        for (int i =0; i < s.length(); i++) {
            if (ss[i] == '?') {
                char a = 'a';
                while((i>0 && a == ss[i-1]) || (i < ss.length-1 && ss[i+1] == a)) {
                    a++;
                }
                ss[i] = a;
            }
        }
        return new String(ss);
    }
}