56 lines
1.2 KiB
C++
56 lines
1.2 KiB
C++
#include <vector>
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#include <string>
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#include <format>
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#include <unordered_set>
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#include <iostream>
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/**
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* 386. Lexicographical Numbers
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* Given an integer n, return all the numbers in the range [1, n] sorted in lexicographical order.
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* You must write an algorithm that runs in O(n) time and uses O(1) extra space.
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*/
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class Solution {
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public:
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static std::vector<int> lexicalOrder(int n) {
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auto next = [n](int x) {
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if (10 * x <= n)
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return 10 * x;
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int nx = 1 + x;
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while (!(nx % 10))
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nx /= 10;
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while (nx > n)
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nx = nx / 10 + 1;
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while (!(nx % 10))
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nx /= 10;
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return nx;
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};
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std::vector<int> ret;
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ret.reserve(n);
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for (int i = 0, j = 1; i < n; ++i, j = next(j))
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ret.push_back(j);
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return ret;
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}
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};
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int main() {
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const int T = 14959;
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auto r = Solution::lexicalOrder(T);
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auto n = r.size();
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std::unordered_set<int> s;
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s.insert(1);
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for (int i = 1; i < n; ++i) {
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if (std::to_string(r[i - 1]) >= std::to_string(r[i]) || r[i] > T || s.contains(r[i])) {
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std::cout << std::format("Conflict: {} and {} at position {}\n", r[i - 1], r[i], i);
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}
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s.insert(r[i]);
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}
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for (int i = 1; i <= n; ++i)
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if (!s.contains(i))
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std::cout << std::format("Missing: {}\n", i);
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return 0;
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}
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