Hello ,
lets start from a basic question that can be solved using Binary number's Knowledge.
Basically in above question you are given n number of poison bottle, and t number of trial you can do ,how many minimum pig you need to find the bottle with poison.
Trick 1
We can Hash any string to bit mask .
Lets start with simple example :-
Count number of different char in string
We can use this trick to reduce the constant factor of 26 in many different kind of problem.
lets take a example
Leetcode Maximum Product of Word Lengths
If you will try to solve this question using boolean array the time complexity will be O(n*n*26) that will lead to tle but you can improve time complexty to O(n*n) just by using bitmask
Trick 2
Printing all subset of K
What do I mean by subset
let say we have number whose binary representation is 1011 then we keep 0 as it is and we can make 1 to 0 or can keep 1.
Subsets of 1011 are 0011 , 1010 , 1011 and so on . 1100 is not subset because we will keep zero at place of zero.
so how many total number of subset will be there for any number
Now First question is How to generate all possible subset
void generate(int k) {
int num = k;
while (k) {
cout << k << " ";
k--;
k = k & num;
}
cout << 0 << '\n';
}
There are Many Question you can solve using this trick . SOS dp also uses this trick Sos Dp.
Lets see some Question:-
Leetcode Number of Valid Words for Each Puzzle
Some Questions To Practice :