8. hashing

Hash Array:

pre-storing in a hash array/ freq array to reduce time complexity 

------------------------------------------------------------------------------------------------------------                            Character hashing-              

   1. without hashing-


  2.  with hashing-

     or

-------------------------------------------------------------------------------------------------------------                                                                        Mapping-

-------------------------------------------------------------------------------------------------------------
NOTE-

1.   Stack overflow/ segmentation fault-      more memory used.

runtime error- accessing index not available.

2.   maxsize(int arr) : 10^6 (inside main),  10^7 (globally)

3.   a-97,  A-65,  total alphabets- 26

4. first priority to choose is unordered map, if TLE occurs then choose map

unordered map- O(1),   worst case: O(N)
ordered map-     O(logN)

5. in a map, any data type can be a key while it is not so in an unordered map 
-------------------------------------------------------------------------------------------------------------                                                            COLLISIONS-(u may ignore)

collision is when similar wale goes to same hash place.



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