1000252. 无重复字符的最长子串

难度: Medium

题目描述

English description is not available for the problem. Please switch to Chinese.

解题思路

代码实现

解决方案

java

class Solution {
    public int lengthOfLongestSubstring(String s) {
        Map<Character, Integer> occ = new HashMap<>();

        int n = s.length();
        int rk = -1, ans = 0;

        for (int i = 0; i < n; i++) {
            if (i != 0) {
                // 左指针向右移动一格，移除一个字符
                occ.remove(s.charAt(i - 1));
            }

            // 清除相同字符前的所有字符
            while (rk + 1 < n && occ.get(s.charAt(rk + 1)) == null) {
                occ.put(s.charAt(rk + 1), rk + 1);
                ++rk;
            }
            ans = Math.max(ans, rk - i + 1);
            if (rk + 1 < n) {
                int rI = occ.get(s.charAt(rk + 1));
                occ = occ.entrySet().stream()
                        .filter(entry -> entry.getValue() >= rI)
                        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
            }

        }

        return ans;

    }
}