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// @Title: 无重复字符的最长子串 (Longest Substring Without Repeating Characters)
// @Author: 15816537946@163.com
// @Date: 2022-01-31 20:18:38
// @Runtime: 4 ms
// @Memory: 2.1 MB
//struct Solution;

use std::cmp::max;
use std::collections::HashMap;

impl Solution {
    pub fn length_of_longest_substring(s: String) -> i32 {
        let mut ans = 0;
        let mut before = -1;
        let mut current = 0;
        let mut m = HashMap::new();

        for c in s.chars() {
            if let Some(last) = m.insert(c, current) {
                before = max(before, last);
            }
            ans = max(ans, current - before);
            current += 1;
        }

        ans
    }
}