[Solved] Project Euler 8 C++ Debug [closed]

by


Adding to Igor Tandetnik’s answer:

There is another problem, (n[i]-'0')*(n[i+1]-'0')*(n[i+2]-'0')*(n[i+3]-'0')*(n[i+4]-'0')*(n[i+5]-'0')*(n[i+6]-'0')*(n[i+7]-'0')*(n[i+8]-'0')*(n[i+9]-'0')*(n[i+10]-'0')*(n[i+11]-'0')*(n[i+12]-'0') is calculated as an int and therefore it will overflow for example at i == 88. You have to cast the first value to unsigned long long to have the whole calculation as unsigned long long.

#include <iostream>
#include <string>
using namespace std;
int main(){
    const string n="7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
    unsigned long long int mx=0;
    for(size_t i=0; i< n.length() - 12; i++){

        unsigned long long int ths= (unsigned long long)(n[i]-'0')*(n[i+1]-'0')*(n[i+2]-'0')*(n[i+3]-'0')*(n[i+4]-'0')*(n[i+5]-'0')*(n[i+6]-'0')*(n[i+7]-'0')*(n[i+8]-'0')*(n[i+9]-'0')*(n[i+10]-'0')*(n[i+11]-'0')*(n.at(i+12)-'0');
        if(ths>mx){
            mx=ths;

        }
    }

    cout<<mx;
}

will print 23514624000.

solved Project Euler 8 C++ Debug [closed]