题解 | #长度为 K 的重复字符子串#

using System;
using System.Collections.Generic;


class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param s string字符串
     * @param k int整型
     * @return int整型
     */
    public int numKLenSubstrRepeats (string s, int k) {
        // write code here
        if (string.IsNullOrWhiteSpace(s) || s.Length < k)
            return 0;
        int nRtnCount = 0;
        for (int nIndex = k - 1; nIndex <= s.Length - 1; nIndex++) {
            string strSub = s.Substring(nIndex - k + 1, k);
            for (int i = nIndex - k + 1; i <= nIndex; i++) {
                if (strSub.IndexOf(s[i]) != strSub.LastIndexOf(s[i])) {
                    nRtnCount++;
                    break;
                }
            }
        }
        return nRtnCount;
    }
}