feat(LeetCode): Solve leetcode/leetcoding_challenge/2025/jun2025/week2/lexicographical_numbers.cpp

Author: htbkoo

src/onlinePlatform/leetcode/leetcoding_challenge/2025/jun2025/week2/lexicographical_numbers.cpp

@@ -0,0 +1,68 @@
+#include <algorithm>
+#include <vector>
+#include <queue>
+#include <set>
+#include <limits>
+#include <map>
+#include <unordered_set>
+#include <unordered_map>
+#include <iterator>
+#include <sstream>
+#include <iostream> // includes cin to read from stdin and cout to write to stdout
+using namespace std; // since cin and cout are both in namespace std, this saves some text
+
+class Solution {
+public:
+    vector<int> lexicalOrder(int n) {
+        vector<int> answer;
+
+        vector<int> stack;
+        stack.push_back(1);
+
+        // in-order
+        while (stack.size() > 0) {
+            auto v = stack.back();
+            stack.pop_back();
+
+            if (v > n) {
+                continue;
+            }
+
+            answer.push_back(v);
+
+            if (v % 10 < 9) {
+                stack.push_back(v + 1);
+            }
+            stack.push_back(v * 10);
+        }
+
+        return answer;
+    }
+};
+
+class WASolution {
+public:
+    vector<int> lexicalOrder(int n) {
+        vector<int> answer;
+
+        deque<int> q;
+        q.push_back(1);
+
+        // in-order
+        while (q.size() > 0) {
+            auto v = q.front();
+            q.pop_front();
+
+            if (v > n) {
+                continue;
+            }
+
+            answer.push_back(v);
+
+            q.push_back(v * 10);
+            q.push_back(v + 1);
+        }
+
+        return answer;
+    }
+};