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Numerical Answer Type Que?

(please Try to give some ahortcut trick also or important concept is there to solve that question ) 

in Algorithms
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number of slots in hash table = 7 (from 0 to 6)

hash function is h(k)=((10k+4)mod c) mod 7

we want no collision hence hash function should point us to unique slots of hash table for each key

 

we know that if we do mod 7 then result will be between (0,1,2,3,4,5,6)

 

first necessary condition for no collision is that for each key (10k+4) mod c should give unique result so we want 7 unique result and it is only possible if c>6 because if c=6 then we will get only 6 unique result(0,1,2,3,4,5)but we want seven unique results as we have  7 keys who wants 7 unique slots.

 

assume

H=(10k+4) mod c

so our final  hash function is h(k)= H mod 7

so take c = 7 and firstly do find H for each key(k)

if for each key it is unique then only go and do mod 7 which is outside

i used gate calculator to do that

so i did for c=7 but not got unique slots for each key

so i tried one by one for c= 8,9,10,11,12 but i got some duplicate slots in each c value till now,

now  when i did with c=13 i got all unique slots

then i did final mod 7 and got that if c=13 then all keys went to different slots and hence no collision.

 

so our hash function must be

h(k)=((10k+4)mod 13) mod 7  in order to avoid any collision while inserting given keys in hash table.

 

hence using this hash function finally our hash table is :

 

Hash Table
   Index                keys
0           36
1           92
2           33
3           61
4           52
5          56
6          47

 

 

edited by

4 Comments

@Ray Tomlinson   is it fine now?

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ys !
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