没有重复的最长字符串
例子说明
Example 1:
Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
Example 2:
Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.
Example 3:
Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
Example 4:
Input: s = ""
Output: 0
Constraints:
0 <= s.length <= 5 * 104
s consists of English letters, digits, symbols and spaces.
知识点
题目分析
- 看到‘请找到满足xx的最x的区间（子串、子数组）的xx’这种题目，我想到用滑动窗口来解决。如果不了解滑动窗口原理，建议先去了解！
/**
index[128]保存的是该字符的下一个坐标值
start表示滑动窗口的开始坐标
*/
int lengthOfLongestSubstring(char * s){
int i, count = 0, max = 0, index[128] = {0}, start = 0;
for(i=0; s[i] != ' '; i++)
{
if(index[s[i]] > start)
{
//表示当前窗口最大值
count = i - start;
if(count > max)
{
max = count;
}
start = index[s[i]];
}
index[s[i]] = i + 1;
}
//当为空串或者串中没有重复的字符的情况
count = i - start;
return count > max? count : max;
}