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
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## 题目描述
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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。
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## 解题思路
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```java
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public int longestSubStringWithoutDuplication(String str) {
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int curLen = 0;
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int maxLen = 0;
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int[] preIndexs = new int[26];
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Arrays.fill(preIndexs, -1);
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for (int curI = 0; curI < str.length(); curI++) {
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int c = str.charAt(curI) - 'a';
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int preI = preIndexs[c];
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if (preI == -1 || curI - preI > curLen) {
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curLen++;
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} else {
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maxLen = Math.max(maxLen, curLen);
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curLen = curI - preI;
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}
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preIndexs[c] = curI;
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}
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maxLen = Math.max(maxLen, curLen);
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return maxLen;
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}
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```
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2019-11-02 14:39:13 +08:00
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<div align="center"><img width="320px" src="https://cs-notes-1256109796.cos.ap-guangzhou.myqcloud.com/githubio/公众号二维码-1.png"></img></div>
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