Add day17

Jongeun/Day17/215_KthLargestElementinanArray.cpp

@@ -0,0 +1,17 @@
+class Solution
+{
+public:
+    int findKthLargest(vector<int> &nums, int k)
+    {
+        priority_queue<int, std::vector<int>, std::less<int>>
+            mq(nums.begin(), nums.end());
+
+        while (k > 1)
+        {
+            k--;
+            mq.pop();
+        }
+
+        return mq.top();
+    }
+};

Jongeun/Day17/40_CombinationSumII.cpp

@@ -0,0 +1,37 @@
+class Solution
+{
+public:
+    vector<vector<int>> combinationSum2(vector<int> &candidates, int target)
+    {
+
+        vector<vector<int>> res;
+        vector<int> comb;
+        std::sort(candidates.begin(), candidates.end());
+        _combinationSum2(res, candidates, comb, 0, target);
+        return res;
+    }
+
+    void _combinationSum2(vector<vector<int>> &res, vector<int> &candidates, vector<int> &comb, int start, int left)
+    {
+        if (left == 0)
+        {
+            res.push_back(comb);
+            return;
+        }
+        else if (left < 0)
+        {
+            return;
+        }
+
+        for (int i = start; i < candidates.size(); i++)
+        {
+            if (i > start && candidates[i] == candidates[i - 1])
+            {
+                continue;
+            }
+            comb.push_back(candidates[i]);
+            _combinationSum2(res, candidates, comb, i + 1, left - candidates[i]);
+            comb.pop_back();
+        }
+    }
+};

Jongeun/Day17/90_SubsetsII.cpp

@@ -0,0 +1,53 @@
+class Solution
+{
+public:
+    vector<vector<int>> subsetsWithDup(vector<int> &nums)
+    {
+        vector<vector<int>> res;
+        unordered_map<int, int> m;
+        for (auto i : nums)
+        {
+            m[i]++;
+        }
+
+        vector<int> keys;
+        int steps{};
+        for (auto &i : m)
+        {
+            keys.push_back(i.first);
+        }
+
+        steps = keys.size();
+
+        vector<int> powerSet;
+        _subsetsWithDup(res, powerSet, m, keys, steps);
+        return res;
+    }
+
+    void _subsetsWithDup(vector<vector<int>> &res, vector<int> &powerSet, unordered_map<int, int> &m, vector<int> &keys, int step)
+    {
+        if (step == 0)
+        {
+            res.push_back(powerSet);
+            return;
+        }
+
+        for (int i = 0; i < m[keys[step - 1]] + 1; i++)
+        {
+            if (i == 0)
+            {
+                _subsetsWithDup(res, powerSet, m, keys, step - 1);
+            }
+            else
+            {
+                powerSet.push_back(keys[step - 1]);
+                _subsetsWithDup(res, powerSet, m, keys, step - 1);
+            }
+        }
+
+        for (int i = 0; i < m[keys[step - 1]]; i++)
+        {
+            powerSet.pop_back();
+        }
+    }
+};