46 lines
1.0 KiB
C++
46 lines
1.0 KiB
C++
#include "stringutils.h"
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// Compute Levenshtein Distance
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// Martin Ettl, 2012-10-05
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size_t LevenshteinDistance(const std::string &s1, const std::string &s2)
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{
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const size_t m(s1.size());
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const size_t n(s2.size());
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if (m == 0) return n;
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if (n == 0) return m;
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size_t *costs = new size_t[n + 1];
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for (size_t k = 0; k <= n; k++) costs[k] = k;
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size_t i = 0;
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for (std::string::const_iterator it1 = s1.begin(); it1 != s1.end(); ++it1, ++i)
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{
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costs[0] = i+1;
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size_t corner = i;
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size_t j = 0;
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for (std::string::const_iterator it2 = s2.begin(); it2 != s2.end(); ++it2, ++j)
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{
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size_t upper = costs[j+1];
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if (*it1 == *it2)
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{
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costs[j+1] = corner;
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}
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else
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{
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size_t t(upper < corner ? upper : corner);
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costs[j + 1] = (costs[j] < t ? costs[j] : t) + 1;
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}
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corner = upper;
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}
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}
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size_t result = costs[n];
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delete [] costs;
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return result;
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}
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