48 lines
1.1 KiB
C
48 lines
1.1 KiB
C
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#include "cache.h"
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#include "levenshtein.h"
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int levenshtein(const char *string1, const char *string2,
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int w, int s, int a, int d)
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{
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int len1 = strlen(string1), len2 = strlen(string2);
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int *row0 = xmalloc(sizeof(int) * (len2 + 1));
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int *row1 = xmalloc(sizeof(int) * (len2 + 1));
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int *row2 = xmalloc(sizeof(int) * (len2 + 1));
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int i, j;
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for (j = 0; j <= len2; j++)
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row1[j] = j * a;
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for (i = 0; i < len1; i++) {
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int *dummy;
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row2[0] = (i + 1) * d;
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for (j = 0; j < len2; j++) {
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/* substitution */
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row2[j + 1] = row1[j] + s * (string1[i] != string2[j]);
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/* swap */
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if (i > 0 && j > 0 && string1[i - 1] == string2[j] &&
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string1[i] == string2[j - 1] &&
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row2[j + 1] > row0[j - 1] + w)
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row2[j + 1] = row0[j - 1] + w;
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/* deletion */
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if (j + 1 < len2 && row2[j + 1] > row1[j + 1] + d)
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row2[j + 1] = row1[j + 1] + d;
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/* insertion */
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if (row2[j + 1] > row2[j] + a)
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row2[j + 1] = row2[j] + a;
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}
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dummy = row0;
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row0 = row1;
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row1 = row2;
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row2 = dummy;
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}
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i = row1[len2];
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free(row0);
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free(row1);
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free(row2);
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return i;
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}
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