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49 lines
2.6 KiB
C
49 lines
2.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2024 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/mem/alg.h"
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#include "libc/mem/mem.h"
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#include "libc/str/str.h"
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#define MIN3(a, b, c) \
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((a) < (b) ? ((a) < (c) ? (a) : (c)) : ((b) < (c) ? (b) : (c)))
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/**
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* Computes similarity between two strings.
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*/
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double levenshtein(const char *s0, const char *s1) {
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int n0 = strlen(s0) + 1;
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int n1 = strlen(s1) + 1;
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int *col = (int *)malloc(n1 * sizeof(int));
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int *pol = (int *)malloc(n1 * sizeof(int));
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for (int i = 0; i < n1; i++)
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pol[i] = i;
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for (int i = 0; i < n0; i++) {
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col[0] = i;
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for (int j = 1; j < n1; j++)
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col[j] = MIN3(1 + col[j - 1], 1 + pol[j],
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pol[j - 1] + !(i > 0 && s0[i - 1] == s1[j - 1]));
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int *t = col;
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col = pol;
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pol = t;
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}
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int dist = pol[n1 - 1];
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free(pol);
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free(col);
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return 1 - dist / ((n0 > n1 ? n0 : n1) - 1.);
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}
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