Help needed in problem D from today's LeetCode Weekly contest

Revision en1, by meiniak, 2020-08-16 13:40:23

Here is the problem link and the solution. I have wrote a recusive solution with memoization to not re compute the sub-problems which have been computed. But i am getting Runtime error due to too much memory allocation in unordered map. How can i optimize it to get A.C ?

My solution : ~~~~~ class Solution { public: unordered_map<long,long> memo; int minDays(int n) { long long num = n; int cnt = 0;

return (int)recur(n);
}

long long recur(long long n){
if(n==0) return 0;
else if(memo.find(n)!=memo.end()){
return memo[n];
}
else{
long long a = n%3 == 0 ? 1 + recur(n-(2*n)/3) : INT_MAX;
long long b = n%2 == 0 ? 1 + recur(n-(n/2)) : INT_MAX;
long long c = 1 + recur(n-1);
vector<long long> v = {a,b,c};
memo[n] = *min_element(v.begin(),v.end());
return memo[n];
}
}

}; ~~~~~ #### History

Revisions Rev. Lang. By When Δ Comment
en2 meiniak 2020-08-16 13:43:05 203
en1 meiniak 2020-08-16 13:40:23 1129 Initial revision (published)