C# 264ms faster than 90.49% - Short and simple
\npublic class Solution\n{\n    public string[] ReorderLogFiles(string[] logs)\n    {\n        List<string> letterLogs = new List<string>();\n        letterLogs
```\npublic class Solution\n{\n    public string[] ReorderLogFiles(string[] logs)\n    {\n        List<string> letterLogs = new List<string>();\n        letterLogs.AddRange(logs.Where(x => !isDigit(x)).\n            OrderBy( y => y.Split(\' \', 2)[1]).\n            ThenBy(z => z.Split(\' \', 2)[0]));\n        letterLogs.AddRange(logs.Where(isDigit));\n        return letterLogs.ToArray();\n    }\n    private bool isDigit(string item)\n    {\n        return char.IsDigit(item[item.IndexOf(\' \') + 1]);\n    }\n}\n```
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