feat: 100_same_tree

100_same_tree/main.cpp

@@ -0,0 +1,31 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct TreeNode {
+    int val;
+    TreeNode* left;
+    TreeNode* right;
+    TreeNode() : val(0), left(nullptr), right(nullptr) {}
+    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+    TreeNode(int x, TreeNode* left, TreeNode* right) : val(x), left(left), right(right) {}
+};
+
+class Solution {
+   public:
+    bool isSameTree(TreeNode* p, TreeNode* q) {
+        function<bool(TreeNode*, TreeNode*)> dfs = [&](TreeNode* p, TreeNode* q) -> bool {
+            // both p and q are null
+            if (!p && !q) return true;
+
+            // one of p and q is null
+            if (!p || !q) return false;
+
+            // the value of p and q are different
+            if (p->val != q->val) return false;
+
+            return dfs(p->left, q->left) && dfs(p->right, q->right);
+        };
+
+        return dfs(p, q);
+    }
+};

39_combination_sum/main.cpp

@@ -0,0 +1,34 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+   public:
+    vector<vector<int>> combinationSum(vector<int>& candidates, int target) {
+        sort(candidates.begin(), candidates.end());
+
+        vector<vector<int>> result;
+
+        function<void(int, vector<int>)> recursive = [&](int target, vector<int> chosen) {
+            if (target < 0) return;
+            
+            if (target == 0) {
+                result.emplace_back(chosen);
+                return;
+            }
+
+            for (auto x : candidates) {
+                if (chosen.size() > 0 && x > chosen.back()) {
+                    return;
+                }
+
+                chosen.emplace_back(x);
+                recursive(target - x, chosen);
+                chosen.pop_back();
+            }
+        };
+
+        recursive(target, {});
+
+        return result;
+    }
+};