Combination Sum 2

Author: alisamad1

Leetcode_Practice_Questions/LC_40.cpp

@@ -0,0 +1,54 @@
+#include<iostream>
+#include<vector>
+#include<set>
+#include<algorithm>
+using namespace std;
+class Solution {
+public:
+    set<vector<int>> st;
+    void solve(vector<int>& input, int target, vector<int>& current, int sum) {
+        if (sum == target) {
+            st.insert(current);
+            return;
+        }
+        if (sum > target || input.empty()) {
+            return;
+        }
+        int curr = input[0];
+        // skipInput: skip current element
+        vector<int> skipInput(input.begin() + 1, input.end());
+        while (!skipInput.empty() && skipInput[0] == curr) {
+            skipInput.erase(skipInput.begin());
+        }
+        solve(skipInput, target, current, sum);
+        // takeInput: take current element
+        vector<int> takeInput(input.begin() + 1, input.end());
+        current.push_back(curr);
+        solve(takeInput, target, current, sum + curr);
+        current.pop_back(); // backtrack
+    }
+    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
+        sort(candidates.begin(), candidates.end());
+        vector<int> current;
+        solve(candidates, target, current, 0);
+        return vector<vector<int>>(st.begin(), st.end());
+    }
+};
+int main(){
+    Solution sol;
+    vector<int> candidates = {10, 1, 2, 7, 6, 1, 5};
+    int target = 8;
+    vector<vector<int>> result = sol.combinationSum2(candidates, target);
+    cout << "Combinations that sum to " << target << ":" << endl;
+    for (const auto& combo : result) {
+        cout << "[";
+        for (size_t i = 0; i < combo.size(); ++i) {
+            cout << combo[i];
+            if (i < combo.size() - 1) {
+                cout << ",";
+            }
+        }
+        cout << "]" << endl;
+    }
+    return 0;
+}

Leetcode_Practice_Questions/LC_79.cpp

@@ -17,7 +17,10 @@ class Solution{
         }
         char temp = board[i][j];
         board[i][j] = '\0';
-        bool found = backtrack(i + 1, j, k + 1) || backtrack(i - 1, j , k + 1) || backtrack(i, j + 1,  k + 1) || backtrack(i , j - 1, k + 1);
+        bool found = backtrack(i + 1, j, k + 1) ||
+                     backtrack(i - 1, j , k + 1) || 
+                     backtrack(i, j + 1,  k + 1) ||
+                      backtrack(i , j - 1, k + 1);
         board[i][j] = temp;
         return found;
     }