ARST打卡第318周

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impl Solution {
    pub fn lexical_order(n: i32) -> Vec<i32> {
        let mut result = Vec::new();
        
        fn dfs(current: i32, n: i32, result: &mut Vec<i32>) {
            if current > n {
                return;
            }
            result.push(current);
            
            // 尝试在当前数字后面添加0-9
            for i in 0..=9 {
                let next = current * 10 + i;
                if next > n {
                    break;
                }
                dfs(next, n, result);
            }
        }
        
        // 从1-9开始，按字典序遍历
        for i in 1..=9 {
            if i > n {
                break;
            }
            dfs(i, n, &mut result);
        }
        
        result
    }
}

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class Solution {
public:
    vector<int> lexicalOrder(int n) {
        vector<int> ret(n);
        int number = 1;
        for (int i = 0; i < n; i++) {
            ret[i] = number;
            if (number * 10 <= n) {
                number *= 10;
            } else {
                while (number % 10 == 9 || number + 1 > n) {
                    number /= 10;
                }
                number++;
            }
        }
        return ret;
    }
};