private void button6_Click(object sender, EventArgs e)
{
//https://www.youtube.com/watch?v=SAiTh4F401k
//construct a square
//update 5/13/2015 watch the video before understanding the logic
int[,] matrix = new int[, ] {
{ 2, -1, -4, -20 },
{ -3, 4, 2, 1 },
{ 8, 10, 1, 3 },
{ -1, 1, 7, -6 }
};
//test
//int[,] matrix = new int[,] { {1,1,1,1},
// {1,1,1,1},
// {1,1,1,1},
// {1,1,1,1}};
SubSquareSum result = FindSubSquareWithMaxSum2(matrix);
StringBuilder sb = new StringBuilder();
if (result != null)
{
sb.Append("Row vaue: ").Append(result.Row).Append(" , ");
sb.Append("Col vaue: ").Append(result.Col).Append(" , ");
sb.Append("Size: ").Append(result.Size).Append(" , ");
sb.Append("Sum : ").Append(result.Sum);
}
else
{
sb.Append("No squares found");
}
this.textBox6.Text = sb.ToString();
}
//This methods finds all the possible subsquares by size basis and compute the sum for each subsuare and return the max
public SubSquareSum FindAllPossibleSubSquareBySize(int[,] matrix, int size)
{
SubSquareSum max = new SubSquareSum(-1, -1, -1, Int32.MinValue);
//For a given square of size n, there are (n - sz + 1) squares of length sz
//that is for n = 5 there will be only 1 square..for n = 4 there will be two on first row..two on second row..
//count is no of possible square for the given size on a particualr row or column..count is same for row and column bcoz square row and col length is same
int count = matrix.GetLength(0) - size + 1;
//size =5 count = 1
//size =4 count = 2
//loop through rows
for (int i = 0; i < count; i++)
{
//loop through colums
for (int j = 0; j < count; j++)
{
int sum = FindSumofCellBySize(matrix, i, j, size);
if (sum > max.Sum)
{
max = new SubSquareSum(i, j, size, sum);
}
}
}
return((max.Sum == Int32.MinValue) ? null : max);
}
private void button7_Click(object sender, EventArgs e)
{
//construct a square
int[,] matrix = new int[, ] {
{ 2, -1, -4, -20 },
{ -3, 4, 2, 1 },
{ 8, 10, 1, 3 },
{ -1, 1, 7, -6 }
};
SubSquareSum result = FindSubSquareWithMaxSum(matrix);
StringBuilder sb = new StringBuilder();
if (result != null)
{
sb.Append("Row vaue: ").Append(result.Row).Append(" , ");
sb.Append("Col vaue: ").Append(result.Col).Append(" , ");
sb.Append("Size: ").Append(result.Size).Append(" , ");
sb.Append("Sum : ").Append(result.Sum);
}
else
{
sb.Append("No squares found");
}
this.textBox6.Text = sb.ToString();
}
public SubSquareSum FindSubSquareWithMaxSum(int[,] matrix)
{
SubSquareSum max = new SubSquareSum(-1, -1, -1, Int32.MinValue);
//To get all possible square go with the window approach n, n-1,,n-2 to 1
//n = 4 4,3,2,1
for (int i = matrix.GetLength(0); i >= 1; i--)
{
SubSquareSum resultbysize = FindAllPossibleSubSquareBySize(matrix, i);
if (resultbysize.Sum > max.Sum)
{
max = resultbysize;
}
}
return((max.Sum == Int32.MinValue) ? null : max);
}
public SubSquareSum FindSubSquareMaxWithDynamicProgramming(int[,] original)
{
int max = Int32.MinValue;
//SubSquareSum maxsubsquare = new SubSquareSum(-1, -1, -1, Int32.MinValue);
SubSquareSum maxsubsquare = null;
int rowcount = original.GetLength(0);
int colcount = original.GetLength(1);
int[,] summatrix = ProcessMatrixToHoldSumValue(original);
//for (int row1 = 0; row1 < rowcount; row1++)
//{
// for (int row2 = row1; row2 < rowcount; row2++)
// {
// for (int col1 = 0; col1 < colcount; col1++)
// {
// for (int col2 = col1; col2 < colcount; col2++)
// {
// int sum = ComputeSum(summatrix, row1, row2, col1, col2);
// if(max < sum )
// {
// maxsubsquare = new SubSquareSum(row1, col1, -1, sum);
// }
// //max = Math.Max(max, ComputeSum(summatrix, row1, row2, col1, col2));
// }
// }
// }
//}
int sum = ComputeSum(summatrix, 1, 3, 0, 2);
if (max < sum)
{
//maxsubsquare = new SubSquareSum(row1, col1, -1, sum);
}
return(maxsubsquare);
}
public SubSquareSum FindSubSquareWithMaxSum2(int[,] matrix)
{
//int[,] summatrix = ProcessMatrixToHoldSumValue(matrix);
//Here the summatrix will be one size larger than matrix
int[,] summatrix = ProcessMatrixToHoldSumValueMethod2(matrix);
SubSquareSum max = new SubSquareSum(-1, -1, -1, Int32.MinValue);
//To get all possible square go with the window approach n, n-1,,n-2 to 1
//n = 4 4,3,2,1
for (int i = matrix.GetLength(0); i >= 1; i--)
{
SubSquareSum resultbysize = FindAllPossibleSubSquareBySizeOptimized(matrix, i, summatrix);
if (resultbysize.Sum > max.Sum)
{
max = resultbysize;
}
}
return((max.Sum == Int32.MinValue) ? null : max);
}
//This methods finds all the possible subsquares by size basis and compute the sum for each subsuare and return the max
//use the computed matrix and get the sum
public SubSquareSum FindAllPossibleSubSquareBySizeOptimized(int[,] matrix, int size, int[,] summatrix)
{
SubSquareSum max = new SubSquareSum(-1, -1, -1, Int32.MinValue);
//For a given square of size n, there are (n - sz + 1) squares of length sz
//that is for n = 5 there will be only 1 square..for n = 4 there will be two on first row..two on second row..
//count is no of possible square for the given size on a particualr row or column..count is same for row and column bcoz square row and col length is same
int count = matrix.GetLength(0) - size + 1;
//size =5 count = 1
//size =4 count = 2
//loop through rows
for (int i = 0; i < count; i++)
{
//loop through colums
for (int j = 0; j < count; j++)
{
//we have starting point i, j
//get the end point from size
int row1 = i;
int col1 = j;
int row2 = (i + size - 1);
int col2 = (j + size - 1);
//we have starting and ending point.find sum from the optimized processed matrix
int sum = ComputeSumMethod2(summatrix, row1, row2, col1, col2);
if (sum > max.Sum)
{
max = new SubSquareSum(row1, col1, size, sum);
}
}
}
return((max.Sum == Int32.MinValue) ? null : max);
}
