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day 13
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day 13
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#include <string>
#include <vector>
#include <iostream>
int main()
{
// store each digit separately
// input has 50 digits
// highest digits might overflow and require a few extra digits
// (I believe +2 would suffice, too)
const unsigned int MinDigits = 50 + 10;
// all digits are initially zero, least significant has index 0
std::vector<unsigned int> sum(MinDigits, 0);
// the resulting number will be sum[0] + 10*sum[1] + 100*sum[2] + ...
unsigned int numbers = 100;
//#define ORIGINAL
#ifndef ORIGINAL
std::cin >> numbers;
#endif
while (numbers--)
{
// read a single number as a string
std::string strAdd;
std::cin >> strAdd;
// convert to digits
std::vector<unsigned int> add;
// process string in reverse: least significant digits first
for (auto i = strAdd.rbegin(); i != strAdd.rend(); i++)
add.push_back(*i - '0'); // convert from ASCII
// fill high/unused positions with zeros
add.resize(sum.size(), 0);
// add all digits
for (unsigned int i = 0; i < add.size(); i++)
{
sum[i] += add[i];
// overflow ? => sum[i] is 10 .. 18
if (sum[i] >= 10)
{
sum[i + 1]++; // sum[i + 1] = sum[i] % 10
sum[i] -= 10; // sum[i] %= 10
}
}
}
// skip high zeros
auto i = sum.rbegin();
while (*i == 0)
i++;
// print first ten digits
unsigned int numDigits = 10;
while (numDigits-- > 0)
std::cout << *i++;
return 0;
}