How to send int[][] as a byte array through Serial
In the comment you write that the receiving end is an Arduino too. Then you can send the data in binary form.

To send the array: 

Serial.write((byte*) arr, sizeof(arr));



(byte*) is cast of the memory location of arr to a byte array
sizeof returns the size of the array in bytes


To receive the binary data you must know the size. Here we read 100 16-bit integers:

Serial.readBytes((byte*) arr, 100 * sizeof(short));


Function readBytes is one of the 'timed' functions of Stream. It waits for the next byte (until timeout).

If one Arduino is 8-bit and the second is 32-bit, then use the type short instead of int, because the size of type int is different, but the type short is 16 bit long on all Arduinos.