Question

I am solving SPOJ problem FLIB and I have tried implementing this using Maps like this –

long long FiboSum(long long n) {
    if(n==1||n==0) return n;
    if(fiboDict.count(n)) return (long long) fiboDict.at(n);
    if(n%2==0) { 
        //calculate term -- value to that key
        fiboDict.insert(pair<long,long>(n,term));
    }
    else { 
        //calculate term
        fiboDict.insert(pair<long,long>(n,term));
    }
    return (long long) fiboDict.at(n);
}

fiboDict is the map, but the problem needs me to calculate for ( 0 <= n < 2^51) but KEY value can’t hold such high values, and I am getting Error

terminate called after throwing an instance of 'std::out_of_range' what():  
map::at

How could I make it hold large values? or If there is alternative then please suggest.

Answer 1

Why dont you make map of :

pair<long long,long long>

then?