Sum and product puzzle: Difference between revisions
→{{header|C sharp}}
Line 406:
free_list(&candidates);
return 0;
}</lang>
{{out}}
<pre>2352 candidates
145 candidates
86 candidates
one candidate
[4, 13] S=17 P=52</pre>
=={{header|C++}}==
{{trans|C}}
<lang cpp>#include <algorithm>
#include <iostream>
#include <map>
#include <vector>
std::ostream &operator<<(std::ostream &os, std::vector<std::pair<int, int>> &v) {
for (auto &p : v) {
auto sum = p.first + p.second;
auto prod = p.first * p.second;
os << '[' << p.first << ", " << p.second << "] S=" << sum << " P=" << prod;
}
return os << '\n';
}
void print_count(const std::vector<std::pair<int, int>> &candidates) {
auto c = candidates.size();
if (c == 0) {
std::cout << "no candidates\n";
} else if (c == 1) {
std::cout << "one candidate\n";
} else {
std::cout << c << " candidates\n";
}
}
auto setup() {
std::vector<std::pair<int, int>> candidates;
// numbers must be greater than 1
for (int x = 2; x <= 98; x++) {
// numbers must be unique, and sum no more than 100
for (int y = x + 1; y <= 98; y++) {
if (x + y <= 100) {
candidates.push_back(std::make_pair(x, y));
}
}
}
return candidates;
}
void remove_by_sum(std::vector<std::pair<int, int>> &candidates, const int sum) {
candidates.erase(std::remove_if(
candidates.begin(), candidates.end(),
[sum](const std::pair<int, int> &pair) {
auto s = pair.first + pair.second;
return s == sum;
}
), candidates.end());
}
void remove_by_prod(std::vector<std::pair<int, int>> &candidates, const int prod) {
candidates.erase(std::remove_if(
candidates.begin(), candidates.end(),
[prod](const std::pair<int, int> &pair) {
auto p = pair.first * pair.second;
return p == prod;
}
), candidates.end());
}
void statement1(std::vector<std::pair<int, int>> &candidates) {
std::map<int, int> uniqueMap;
std::for_each(
candidates.cbegin(), candidates.cend(),
[&uniqueMap](const std::pair<int, int> &pair) {
auto prod = pair.first * pair.second;
uniqueMap[prod]++;
}
);
bool loop;
do {
loop = false;
for (auto &pair : candidates) {
auto prod = pair.first * pair.second;
if (uniqueMap[prod] == 1) {
auto sum = pair.first + pair.second;
remove_by_sum(candidates, sum);
loop = true;
break;
}
}
} while (loop);
}
void statement2(std::vector<std::pair<int, int>> &candidates) {
std::map<int, int> uniqueMap;
std::for_each(
candidates.cbegin(), candidates.cend(),
[&uniqueMap](const std::pair<int, int> &pair) {
auto prod = pair.first * pair.second;
uniqueMap[prod]++;
}
);
bool loop;
do {
loop = false;
for (auto &pair : candidates) {
auto prod = pair.first * pair.second;
if (uniqueMap[prod] > 1) {
remove_by_prod(candidates, prod);
loop = true;
break;
}
}
} while (loop);
}
void statement3(std::vector<std::pair<int, int>> &candidates) {
std::map<int, int> uniqueMap;
std::for_each(
candidates.cbegin(), candidates.cend(),
[&uniqueMap](const std::pair<int, int> &pair) {
auto sum = pair.first + pair.second;
uniqueMap[sum]++;
}
);
bool loop;
do {
loop = false;
for (auto &pair : candidates) {
auto sum = pair.first + pair.second;
if (uniqueMap[sum] > 1) {
remove_by_sum(candidates, sum);
loop = true;
break;
}
}
} while (loop);
}
int main() {
auto candidates = setup();
print_count(candidates);
statement1(candidates);
print_count(candidates);
statement2(candidates);
print_count(candidates);
statement3(candidates);
print_count(candidates);
std::cout << candidates;
return 0;
}</lang>
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