#codingexercises 

Write  a method to delete all the nodes from a binary tree that lie on a path whose sum from root to leaf is less than a given value K.  

Void delPathSums(Node root, int K, ref int cur) 

{ 

If (Root == null) return; 

Cur+= root.data; 

Int left = cur; 

Int right = cur; 

Root.left = delPathSums(root.left , K, ref int left); 

Root.right = delPathSums(root.right, K, ref int right); 

Cur += max(left, right); 

If (cur <k){ 

Tree_delete(root); 

Root = null; 

} 

Return root; 

}

Merge k sorted arrays

List<int> mergeSorted(List<List<int>> sorted, int k, int m)

{

Var result = new List<int>();

Var cur = new List<int> (); // local index

For(int k =0; k <  m×k ; k++)

{

Var min = getMin(sorted, ref cur);

Result.add(min.first);

Cur[min.second]++;

}

Return result;

}

Tuple<int,int> GetMin(List<List<int>> sorted, ref List<int>cur)

{

var min = new List<int>();

for (int I = 0; I < cur.Count; i++)

{

if (cur[i] < sorted[i].Count)

min.Add(sorted[i][cur[i]]);

else{

min.Add(INT_MAX);

}

}

int val = min.min();

int index = min.index(x = > x == val);

return new Tuple<int, int>(val, index);

}

This could also be solved with a heap

List<int> mergeSortedWithHeap(List<List<int>> sorted, int k)

{

var ret = new List<int>();

var h = new Heap();

for (int i =0; i  < n*k; i++)

{

var root = h.getMin();

ret[i] = root.data;

if (root.localindex < n)

{

root.data = sorted[root.globalindex][root.localindex];

root.localindex += 1;

}

else root.element = INT_MAX;

h.replaceMin(root);

}

return ret;

}

Given a 2d array find the maximum sum rectangle
int FindMaxSum(int[,] nums, int row, int col)
{
int max = 0;
for (int i =0; i < row; i++)
  for (int j = 0; j < col; j++)
  {
     int cur = 0;
     var start = new Tuple<int, int> (i,j);
     // choose end to be one of the remaining points to the right and bottom of start
      for (int x = i; x < row; x++)
        for (int y = j; y < col; y++)
            if (x !==i && y !== j) 
                cur = GetSum(nums, i, j, x,y); 
                 if (cur > max) max = cur;
  }
}
return max;