Input large strings in C
c, memory-management, string
Solution
If you use malloc, the memory space will create on `HEAP`.
While in the second implementation, the memory locates on `STACK`.
As I know, stack is faster than heap.
Ref: What and where are the stack and heap?
More over, I think declaring the `char` array outside the loop is more reasonable:
char a[100000] = {};
while( t-- )
{
scanf( "%d", &n );
scanf( "%s", a );
....
}
Problem
For a particular problem, I have to take string input from the user which can be of size between `1 and 10^5` . I used the following code ``` char *a; a = malloc(100000*sizeof(char)); ``` and inside a loop ( t refers to number of test cases ) ``` while( t-- ) { scanf( "%d", &n ); scanf( "%s", a ); ..... } ``` n is the length of the string that is input by the user at run time. The problem is this is giving me "Time Limit Exceeded" I made few changes to the above code, ``` while( t-- ) { scanf( "%d", &n ); char a[n]; scanf( "%s", a ); .... } ``` This works perfectly fine without "TLE" . But I don't understand why. The reason for using the first code was that time would be saved since allocation of memory is done only once. Am I wrong? Please explain.