computes the longest increasing path starting from a given locatioin (i, j) @param matrix extended matrix @param longest LIP value matrix @param dirs all valid moving directions @param rows number of rows @param cols number of columns @param i row index @param j column index @return LIP starting fr
(int[][] matrix, int[][] longest, int[][] dirs, int rows, int cols, int i, int j)
source not stored for this graph (policy: none)