Lexicographical Numbers Problem
Description
LeetCode Problem 386.
Given an integer n, return all the numbers in the range [1, n] sorted in lexicographical order. You must write an algorithm that runs inO(n)time and uses O(1) extra space.
Example 1:
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Input: n = 13
Output: [1,10,11,12,13,2,3,4,5,6,7,8,9]
Example 2:
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Input: n = 2
Output: [1,2]
Constraints:
- 1 <= n <= 5 * 10^4
Sample C++ Code
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class Solution {
public:
vector<int> lexicalOrder(int n) {
vector<int> res(n);
int cur = 1;
for (int i = 0; i < n; i++) {
res[i] = cur;
if (cur * 10 <= n) {
cur *= 10;
} else {
if (cur >= n)
cur /= 10;
cur += 1;
while (cur % 10 == 0)
cur /= 10;
}
}
return res;
}
};