ClickHouse/src/Common/levenshteinDistance.cpp

33 lines
716 B
C++

#include <Common/levenshteinDistance.h>
#include <Common/PODArray.h>
namespace DB
{
size_t levenshteinDistance(const String & lhs, const String & rhs)
{
size_t m = lhs.size();
size_t n = rhs.size();
PODArrayWithStackMemory<size_t, 64> row(n + 1);
for (size_t i = 1; i <= n; ++i)
row[i] = i;
for (size_t j = 1; j <= m; ++j)
{
row[0] = j;
size_t prev = j - 1;
for (size_t i = 1; i <= n; ++i)
{
size_t old = row[i];
row[i] = std::min(prev + (std::tolower(lhs[j - 1]) != std::tolower(rhs[i - 1])),
std::min(row[i - 1], row[i]) + 1);
prev = old;
}
}
return row[n];
}
}