时间:2022-05-17 09:25:25 | 栏目:.NET代码 | 点击:次
给定一个字符串,请你找出其中不含有重复字符的 最长子串 的长度。
示例 1:
输入: "abcabcbb"
输出: 3
解释: 因为无重复字符的最长子串是 "abc",所以其长度为 3。
示例 2:
输入: "bbbbb"
输出: 1
解释: 因为无重复字符的最长子串是 "b",所以其长度为 1。
示例 3:
输入: "pwwkew"
输出: 3
解释: 因为无重复字符的最长子串是 "wke",所以其长度为 3。
要注意字符串为空、变量为null、字符串长度 Length = 1 等情况。
测试实例
输入 " " "au" "abcabcbb" "bbbbb" "pwwkew" "aab" 预期结果分别是 1,2,3,1,3,2
代码格式模板
public class Solution { public int LengthOfLongestSubstring(string s) { } }
使用最笨的方式,200ms左右
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(); } } }