1291_Sequential_Digits

Leetcode 1291: Sequential Digits
Detailed video explanation: https://youtu.be/sFt3KVGyeWw
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C++:
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class Solution {
public:
    vector<int> sequentialDigits(int low, int high) {
        string digits = "123456789";
        vector<int> result;
        int nl = to_string(low).length();
        int nh = to_string(high).length();
        
        for(int i = nl; i <= nh; ++i){
            for(int j = 0; j < 10-i; ++j){
                int num = stoi(digits.substr(j, i));
                if(num >= low && num <= high) result.push_back(num);
            }
        }
        return result;
    }
};



Java:
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class Solution {
    public List<Integer> sequentialDigits(int low, int high) {
        String digits = "123456789";
        List<Integer> result = new ArrayList();
        int nl = String.valueOf(low).length();
        int nh = String.valueOf(high).length();
        
        for(int i = nl; i <= nh; ++i){
            for(int j = 0; j < 10-i; ++j){
                int num = Integer.parseInt(digits.substring(j, j+i));
                if(num >= low && num <= high) result.add(num);
            }
        }
        return result;
    }
}




Python3:
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class Solution:
    def sequentialDigits(self, low: int, high: int) -> List[int]:
        digits = "123456789"
        result = []
        nl, nh = len(str(low)), len(str(high))
        
        for i in range(nl, nh+1):
            for j in range(0, 10-i):
                num = int(digits[j: j+i])
                if num >= low and num <= high: result.append(num)
        return result