CS-Notes/notes/48. 最长不含重复字符的子字符串.md
2019-11-02 12:07:41 +08:00

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# 48. 最长不含重复字符的子字符串
## 题目描述
输入一个字符串只包含 a\~z 的字符求其最长不含重复字符的子字符串的长度例如对于 arabcacfr最长不含重复字符的子字符串为 acfr长度为 4
## 解题思路
```java
public int longestSubStringWithoutDuplication(String str) {
int curLen = 0;
int maxLen = 0;
int[] preIndexs = new int[26];
Arrays.fill(preIndexs, -1);
for (int curI = 0; curI < str.length(); curI++) {
int c = str.charAt(curI) - 'a';
int preI = preIndexs[c];
if (preI == -1 || curI - preI > curLen) {
curLen++;
} else {
maxLen = Math.max(maxLen, curLen);
curLen = curI - preI;
}
preIndexs[c] = curI;
}
maxLen = Math.max(maxLen, curLen);
return maxLen;
}
```
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