/// <summary>   
        /// 计算两个字符串的差异距离   
        /// </summary>   
        /// <param name="source">来源字符串</param>   
        /// <param name="target">目标字符串</param>   
        /// <returns>字符串差距</returns>   
        public int CalcDistance(string source, string target)
        {
            int n = source.Length;
            int m = target.Length;
            if (m == 0) return n;
            if (n == 0) return m;
            var matrix = new int[n + 1, m + 1];
            for (int i = 1; i <= n; i++)
            {
                matrix[i, 0] = i;
            }
            for (int i = 1; i <= m; i++)
            {
                matrix[0, i] = i;
            }for (int i = 1; i <= n; i++)
            {
                var si = source[i - 1];
                for (int j = 1; j <= m; j++)
                {
                    var tj = target[j - 1];int cost;
                    if (si == tj)
                        cost = 0;
                    else
                        cost = 1;int above = matrix[i - 1, j] + 1;
                    int left = matrix[i, j - 1] + 1;
                    int diag = matrix[i - 1, j - 1] + cost;
                    matrix[i, j] = Math.Min(above, Math.Min(left, diag));
                }
            }
            return matrix[n, m];
        }

 /// <summary>   
        /// 计算两个字符串的相似度   
        /// </summary>   
        /// <param name="source">来源字符串</param>   
        /// <param name="target">目标字符串</param>   
        /// <returns>相似度</returns>   
        public double CalcSimilarity(string source, string target)
        {
            int n = source.Length;
            int m = target.Length;
            if (n == 0 || m == 0)
                return 0;
            int distance = CalcDistance(source, target);
            int max = Math.Max(n, m);
            return 1.0 * (max - distance) / max;
        }

List<string> lvArea = new List<string>();
            lvArea.Add("北京电信一区");
            lvArea.Add("广东一区");
            lvArea.Add("北京网通二区");
            lvArea.Add("北京网通一区");decimal lvSmall = 100;
            string lvRes = "";
            foreach (string item in lvArea)
            {
                decimal lvTemp = CalcDistance("北京网通二区", item);
                if (lvTemp < lvSmall)
                {
                    lvSmall = lvTemp;
                    lvRes = item;
                }
            }
            MessageBox.Show(lvRes);