Dictionary and int matrix

Dictionaries ——Dictionary

Dictionary commonly used methods ——fo'reach loop

foreach (var item in list)
        {
            //Key Value ：item.Key,value Value ：item.Value;
            // Find the key by the value 
            if (list.ContainsValue(" value "))
            {
                item.Key// Find key 
            }
            // Find value by key 
            if (list.ContainsKey( key ))
            {
                item.Value// Find value 
            }
        }

int matrix ——int[][]

That is, several arrays form a matrix , First, separate the arrays , Look for the elements of the specific array in each array .

int[][] mat;
 for (int i = 0; i < mat.Length; i++)
            {
                for (int j = 0; j < mat[i].Length; j++)// The first i An array 
                {
                    if (mat[i][j] == 1)// The first i The number in the array j Elements 
                    {
                        
                    }
                }
            }