[My solution C language interview series] 008 remove repeated numbers in the array

[My solution C language interview series] 008 remove repeated numbers in the array

Remove repeated numbers in the array

 

There is an array with a size of 100. The numbers in the array are between 1 and 99, but the numbers in the array are repeated. Please write a function to remove the repeated numbers in the array.

# Define init_num-1

Method 1: (the easiest way to think)

Void removebufferrepnum_00 (INT buffer [])

{

Int I, J;

 

For (I = 0; I <buffersize; I ++)

{

For (j = I + 1; j <buffersize; j ++)

{

If (buffer [I] = buffer [J])

{

Buffer [I] = init_num;

Break;

}

}

}

For (I = 0, j = 0; I <buffersize; I ++)

{

If (buffer [I] = init_num)

Continue;

Buffer [J ++] = buffer [I];

}

 

While (j <buffersize)

Buffer [J ++] = init_num;

}

This algorithm is the simplest, and the time complexity is O (n2)

 

Method 2: (use the hash table method)

Void removebufferrepnum_01 (INT buffer [])

{

Int tbuffer [buffersize];

Int I = 0, j = 0;

For (I = 0; I <buffersize; I ++) // initializes the Array

Tbuffer [I] = init_num;

 

For (I = 0; I <buffersize; I ++) // remove an algorithm

{

If (tbuffer [buffer [I] = init_num)

Tbuffer [buffer [I] = buffer [I];

}

 

For (I = 0; I <buffersize; I ++)

{

If (tbuffer [I] = init_num)

Continue;

Buffer [J ++] = tbuffer [I];

}

While (j <buffersize)

Buffer [J ++] = init_num;

}

This method is implemented by enabling the auxiliary space and setting the hash table. It can be executed n times in total. Time Complexity: O (n ). However, the only weakness is that extra space is required.