Problem
https://projecteuler.net/problem=22
Using names.txthttps://github.com/tvarley/euler/blob/master/src/p022_names.txt), a 46K text file containing over five-thousand first names, begin by sorting it into alphabetical order. Then working out the alphabetical value for each name, multiply this value by its alphabetical position in the list to obtain a name score.
For example, when the list is sorted into alphabetical order, COLIN, which is worth 3 + 15 + 12 + 9 + 14 = 53, is the 938th name in the list. So, COLIN would obtain a score of 938 × 53 = 49714.
What is the total of all the name scores in the file?
Answer: 871198282
Solution
#include <cctype>
#include <fstream>
#include <iostream>
#include <map>
#include <sstream>
// TODO: template to a non ascii version and optimize
int alphabet_score(std::string name)
{
int score = 0;
for( char& c : name ){
if( std::isalpha(c)){ // Do not care about quotes
score += toupper(c) - 'A'+1;
}
}
return score;
}
int name_scores(const char* fname)
{
typedef std::map<std::string,int> name_coll;
name_coll names;
std::cout << "Opening: " << fname << std::endl;
std::ifstream fin(fname);
if( !fin.is_open()){
std::cerr << "Failed to open file: " << fname << std::endl;
}
for( std::string line ; std::getline(fin,line);){
std::stringstream ss(line);
std::string name;
while (std::getline(ss,name,',')) {
int score = alphabet_score(name);
// std::cout << "Name: " << name << ':' << score << std::endl;
name_coll::iterator n = names.find(name);
if( n != names.end()){
n->second += score; // Dupe name, just count again
}else{
names.insert( name_coll::value_type(name,score));
}
}
}
int total_score = 0;
int pos = 1;
for( name_coll::iterator itr = names.begin(); itr != names.end() ; itr++, pos++){
// std::cout << "Name: " << pos << ':' << itr->first << ':' << itr->second << std::endl;
total_score += (pos*itr->second);
}
return total_score;
}
#if ! defined UNITTEST_MODE
int main(int argc, char const *argv[]) {
std::cout << "Answer: " << name_scores("./src/p022_names.txt") << std::endl;
}
#endif //#if ! defined UNITTEST_MODE