Add day28

Jongeun/Day28/213_HouseRobberII.cpp

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+class Solution
+{
+public:
+    int rob(vector<int> &nums)
+    {
+
+        if (nums.size() == 1)
+        {
+            return nums[0];
+        }
+
+        int first = 0, second1 = 0;
+
+        for (int i = 0; i < nums.size() - 1; i++)
+        {
+
+            int tempt = first;
+            first = second1;
+            second1 = max(tempt + nums[i], second1);
+        }
+
+        first = 0;
+        int second2 = 0;
+
+        for (int i = 1; i < nums.size(); i++)
+        {
+            int tempt = first;
+            first = second2;
+            second2 = max(tempt + nums[i], second2);
+        }
+
+        return max(second1, second2);
+    }
+};

Jongeun/Day28/295_FindMedianfromDataStream.cpp

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+class MedianFinder
+{
+public:
+    MedianFinder()
+    {
+    }
+
+    void addNum(int num)
+    {
+        if (total == 0)
+        {
+            maxHeap.push(num);
+            total++;
+        }
+        else
+        {
+            if (total % 2 == 0)
+            {
+                if (maxHeap.top() < num)
+                {
+                    minHeap.push(num);
+                    int temp = minHeap.top();
+                    minHeap.pop();
+                    maxHeap.push(temp);
+                }
+                else
+                {
+                    maxHeap.push(num);
+                }
+            }
+            else
+            {
+                if (maxHeap.top() < num)
+                {
+                    minHeap.push(num);
+                }
+                else
+                {
+                    maxHeap.push(num);
+                    int temp = maxHeap.top();
+                    maxHeap.pop();
+                    minHeap.push(temp);
+                }
+            }
+
+            total++;
+        }
+    }
+
+    double findMedian()
+    {
+        if (total % 2 == 0)
+        {
+            return ((double)maxHeap.top() + minHeap.top()) / 2;
+        }
+        else
+        {
+            return maxHeap.top();
+        }
+    }
+
+private:
+    int total = 0;
+    priority_queue<int> maxHeap;
+    priority_queue<int, std::vector<int>, std::greater<int>> minHeap;
+};
+
+/**
+ * Your MedianFinder object will be instantiated and called as such:
+ * MedianFinder* obj = new MedianFinder();
+ * obj->addNum(num);
+ * double param_2 = obj->findMedian();
+ */

Jongeun/Day28/994_RottingOranges.cpp

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+class Solution
+{
+public:
+    int orangesRotting(vector<vector<int>> &grid)
+    {
+        int m = grid.size();
+        int n = grid[0].size();
+        queue<pair<int, pair<int, int>>> q;
+
+        for (int i = 0; i < m; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                if (grid[i][j] == 2)
+                {
+                    q.push({0, {i, j}});
+                }
+            }
+        }
+
+        int totalTime = 0;
+        while (!q.empty())
+        {
+            auto cell = q.front();
+            q.pop();
+
+            int i = cell.second.first;
+            int j = cell.second.second;
+            int time = cell.first;
+
+            if (i < 0 || i >= m || j < 0 || j >= n || grid[i][j] == 0 || grid[i][j] == 3)
+            {
+                totalTime = max(totalTime, time - 1);
+                continue;
+            }
+
+            grid[i][j] = 3; // mark it as already visited
+
+            q.push({time + 1, {i + 1, j}});
+            q.push({time + 1, {i - 1, j}});
+            q.push({time + 1, {i, j + 1}});
+            q.push({time + 1, {i, j - 1}});
+        }
+
+        for (int i = 0; i < m; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                if (grid[i][j] == 1)
+                {
+                    return -1;
+                }
+            }
+        }
+
+        return totalTime;
+    }
+};