示例1

輸出：low = 100, high = 300
輸出：[123,234]

示例2

輸出：low = 1000, high = 13000
輸出：[1234,2345,3456,4567,5678,6789,12345]

提示

• 10 <= low <= high <= 10^9

分析

既然是求順次數，那就順序遍歷出來好啦，貌似沒啥需要分析的…

代碼

class Solution {
public:
    vector<int> sequentialDigits(int low, int high) {
        string str = "123456789";
        string low_str = std::to_string(low);
        int low_len = low_str.size();
        return dfs(str, low_len, low, high);
    }

    vector<int> dfs(string &str, int low_len, int low, int high) {
        vector<int> ret;
        for (int i = low_len; i < 10; ++i) {
            for (int j = 0; j + i <= str.size(); ++j) {
                string tem_str = str.substr(j, i);
                int tem_int = stoi(tem_str);
                if (tem_int > high) {
                    return ret;
                }
                if (tem_int >= low) {
                    ret.push_back(tem_int);
                }
            }
        }
        return ret;
    }

};

  代碼精進之路，我們一起成長！