Created
November 21, 2015 02:32
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template <typename InIt1, typename InIt2, typename OutIt> | |
OutIt unordered_set_intersection(InIt1 b1, InIt1 e1, InIt2 b2, InIt2 e2, OutIt out) { | |
while (!(b1 == e1)) { | |
if (!(std::find(b2, e2, *b1) == e2)) { | |
*out = *b1; | |
++out; | |
} | |
++b1; | |
} | |
return out; | |
} | |
int unorderedSetIntersectionBenchmark() | |
{ | |
const int nBags = 1000; | |
const int maxBagLength = 10; | |
typedef unordered_set<int> Bag; | |
vector<Bag> bags; | |
ifstream input("10000ran.dat"); // http://www.agner.org/random/10000ran.zip | |
int similarity = 0; | |
bags.reserve(nBags); | |
for (int iBag = 0; iBag < nBags; ++iBag) { | |
bags.push_back(Bag()); | |
for (int j = 0; j < maxBagLength; ++j) { | |
string number; | |
getline(input, number, ','); | |
bags.back().insert(round(atof(number.c_str())*maxBagLength)); | |
} | |
} | |
for (int i = 0; i < bags.size(); ++i) | |
for (int j = i+1; j < bags.size(); ++j) { | |
Bag intersec; | |
unordered_set_intersection(bags[i].begin(), bags[i].end(), bags[j].begin(), bags[j].end(), inserter(intersec, intersec.begin())); | |
similarity += intersec.size(); | |
} | |
return similarity; | |
} |
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