C#算法之无重复字符的最长子串

输入
" "
"au"
"abcabcbb"
"bbbbb"
"pwwkew"
"aab"

预期结果分别是 1,2,3,1,3,2

public class Solution {
    public int LengthOfLongestSubstring(string s) {
         
    }
}

public class Solution {
    public int LengthOfLongestSubstring(string s) {
                    if (s == null || s == "")
                return 0;

            char[] a = s.ToCharArray();      //字符串转为字符数组
            int start = 0;                   //区间开始位置
            int stop = 0;                    //区间结束位置
            int newMax = 1;                   //当前区间数
            int max = 1;                     //区间最大个数

            for (stop = 1; stop < a.Length; stop++)   //每次向后移动一位
            {
                bool b = false;                       //是否存在重复
                for (int i = start; i < stop; i++)  //检查当前元素在区间是否有相同值
                {
                    if (a[stop] == a[i])        //如果stop+1位在区间找到相同的字符
                    {
                        char ls = a[stop];
                        if (newMax > max) max = newMax;
                        start = i + 1;              //区间开始位置重置
                        newMax = stop - start + 1;
                        b = true;            
                        break;
                    }
                }
                if (b == false)
                    newMax += 1;
            }
            if (newMax > max) max = newMax;
            return max;
    }
}

using System;

namespace ConsoleApp1
{
    public class Testa
    {
        public int LengthOfLongestSubstring(string s)
        {
            if (s == null || s == "")
                return 0;

            char[] a = s.ToCharArray();      //字符串转为字符数组
            int start = 0;                   //区间开始位置
            int stop = 0;                    //区间结束位置
            int newMax = 1;                   //当前区间数
            int max = 1;                     //区间最大个数

            for (stop = 1; stop < a.Length; stop++)   //每次向后移动一位
            {
                bool b = false;                       //是否存在重复
                for (int i = start; i < stop; i++)  //检查当前元素在区间是否有相同值
                {
                    if (a[stop] == a[i])        //如果stop+1位在区间找到相同的字符
                    {
                        char ls = a[stop];
                        if (newMax > max) max = newMax;
                        start = i + 1;              //区间开始位置重置
                        newMax = stop - start + 1;      //重新设置区间数
                        b = true;            
                        break;
                    }
                }
                if (b == false)             ////没有重新设置区间数时加1
                    newMax += 1;
            }
            if (newMax > max) max = newMax;
            return max;
        }
    }
    class Program
    {


        static void Main(string[] args)
        {
            Testa t1 = new Testa();                                     //正确结果
            Console.WriteLine(t1.LengthOfLongestSubstring(" "));        //1
            Console.WriteLine(t1.LengthOfLongestSubstring("au"));       //2
            Console.WriteLine(t1.LengthOfLongestSubstring("abcabcbb")); //3
            Console.WriteLine(t1.LengthOfLongestSubstring("bbbbb"));    //1
            Console.WriteLine(t1.LengthOfLongestSubstring("pwwkew"));   //3
            Console.WriteLine(t1.LengthOfLongestSubstring("aab"));      //2
            Console.ReadKey();
        }
    }
}

        public int LengthOfLongestSubstring(string s)
        {
            int n = s.Length;
            HashSet<char> set = new HashSet<char>();        //集合
            int ans = 0, start = 0, stop = 0;               //ans为字符串长度，starp区间起点，stop区间终点
            while (start < n && stop < n)
            {
                // try to extend the range [i, j]
                if (!set.Contains(s[stop]))
                {
                    set.Add(s[stop++]);
                    ans = Math.Max(ans, stop - start);
                    //或者ans = ans > (stop - start) ? ans : (stop - start)
                }
                else
                {
                    set.Remove(s[start++]);
                }
            }
            return ans;
        }

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp2
{
    public class Solution
    {
        public int LengthOfLongestSubstring(string s)
        {
            int n = s.Length;
            HashSet<char> set = new HashSet<char>();        //集合
            int ans = 0, start = 0, stop = 0;               //ans为字符串长度，starp区间起点，stop区间终点
            while (start < n && stop < n)
            {
                // try to extend the range [i, j]
                if (!set.Contains(s[stop]))
                {
                    set.Add(s[stop++]);
                    ans = Math.Max(ans, stop - start);
                    //或者ans = ans > (stop - start) ? ans : (stop - start)
                }
                else
                {
                    set.Remove(s[start++]);
                }
            }
            return ans;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {

            Solution t1 = new Solution();                                     //正确结果
            Console.WriteLine(t1.LengthOfLongestSubstring(" "));        //1
            Console.WriteLine(t1.LengthOfLongestSubstring("au"));       //2
            Console.WriteLine(t1.LengthOfLongestSubstring("abcabcbb")); //3
            Console.WriteLine(t1.LengthOfLongestSubstring("bbbbb"));    //1
            Console.WriteLine(t1.LengthOfLongestSubstring("pwwkew"));   //3
            Console.WriteLine(t1.LengthOfLongestSubstring("aab"));      //2
            Console.ReadKey();
        }
    }
}