#include #include #include typedef struct { char *line; int distance; size_t max_len; size_t min_len; size_t common_substring_length; double score; } LineScore; static void freeLineScores(LineScore *lines, const size_t line_count) { for (size_t i = 0; i < line_count; i++) free(lines[i].line); free(lines); } static double damerauLevenshteinSimilarity(const int distance, const size_t max_len) { if (max_len == 0) return 1.0; return 1.0 - (double) distance / (double) max_len; } static bool equals(const char *s1, const char *s2, const size_t len) { for (size_t i = 0; i < len; i++) if (s1[i] != s2[i]) return false; return true; } static size_t maximalCommonSubstringLength(const char *s1, const char *s2) { const size_t len1 = strlen(s1); const size_t len2 = strlen(s2); const size_t max_len = len1 > len2 ? len2 : len1; for (size_t len = max_len; len > 0; len--) for (size_t i = 0; i <= len1 - len; ++i) for (size_t j = 0; j <= len2 - len; ++j) if (equals(s1 + i, s2 + j, len)) return len; return 0; } static double maximalCommonSubstringSimilarity(const size_t common_substring_length, const size_t min_len) { if (min_len == 0) return 0.0; return (double) common_substring_length / (double) min_len; } int damerauLevenshteinDistance(const char *s1, const char *s2) { const size_t len1 = strlen(s1); const size_t len2 = strlen(s2); const size_t width = len2 + 1; int *d = malloc((len1 + 1) * (len2 + 1) * sizeof(*d)); if (d == NULL) { fprintf(stderr, "Failed to allocate distance matrix\n"); exit(EXIT_FAILURE); } for (size_t i = 0; i <= len1; i++) d[i * width] = (int) i; for (size_t j = 0; j <= len2; j++) d[j] = (int) j; for (size_t i = 1; i <= len1; i++) { for (size_t j = 1; j <= len2; j++) { const int cost = (s1[i - 1] == s2[j - 1]) ? 0 : 1; const int deletion = d[(i - 1) * width + j] + 1; const int insertion = d[i * width + (j - 1)] + 1; const int substitution = d[(i - 1) * width + (j - 1)] + cost; int best = deletion < insertion ? deletion : insertion; if (substitution < best) best = substitution; d[i * width + j] = best; if (i > 1 && j > 1 && s1[i - 1] == s2[j - 2] && s1[i - 2] == s2[j - 1]) { const int transposition = d[(i - 2) * width + (j - 2)] + cost; if (transposition < d[i * width + j]) d[i * width + j] = transposition; } } } const int result = d[len1 * width + len2]; free(d); return result; } int comparator(const void *a, const void *b) { auto const ls_a = (const LineScore *)a; auto const ls_b = (const LineScore *)b; if (ls_a->score < ls_b->score) return 1; if (ls_a->score > ls_b->score) return -1; if (ls_a->common_substring_length < ls_b->common_substring_length) return 1; if (ls_a->common_substring_length > ls_b->common_substring_length) return -1; if (ls_a->distance < ls_b->distance) return -1; if (ls_a->distance > ls_b->distance) return 1; return strcmp(ls_a->line, ls_b->line); } int main(const int argc, char *argv[]) { if (argc < 2) { fprintf(stderr, "Usage: %s \n", argv[0]); return 1; } const char *query = argv[1]; const size_t query_len = strlen(query); size_t line_count = 0; size_t capacity = 100; double max_similarity = 0.0; LineScore *lines = malloc(capacity * sizeof(*lines)); if (lines == NULL) { fprintf(stderr, "Failed to allocate result buffer\n"); return 1; } char buffer[4096]; while (fgets(buffer, sizeof(buffer), stdin) != NULL) { size_t len = strlen(buffer); if (len > 0 && buffer[len - 1] == '\n') { buffer[len - 1] = '\0'; len--; } if (line_count >= capacity) { capacity *= 2; LineScore *resized_lines = realloc(lines, capacity * sizeof(*lines)); if (resized_lines == NULL) { fprintf(stderr, "Failed to grow result buffer\n"); freeLineScores(lines, line_count); return 1; } lines = resized_lines; } const int distance = damerauLevenshteinDistance(query, buffer); const size_t max_len = query_len > len ? query_len : len; const size_t min_len = query_len > len ? len : query_len; const double score = damerauLevenshteinSimilarity(distance, max_len); lines[line_count].line = malloc(len + 1); if (lines[line_count].line == NULL) { fprintf(stderr, "Failed to allocate line buffer\n"); freeLineScores(lines, line_count); return 1; } strcpy(lines[line_count].line, buffer); lines[line_count].distance = distance; lines[line_count].max_len = max_len; lines[line_count].min_len = min_len; lines[line_count].common_substring_length = 0; lines[line_count].score = score; if (line_count == 0 || score > max_similarity) { max_similarity = score; } line_count++; } if (max_similarity < 0.5) { for (size_t i = 0; i < line_count; i++) { lines[i].common_substring_length = maximalCommonSubstringLength(query, lines[i].line); lines[i].score = maximalCommonSubstringSimilarity(lines[i].common_substring_length, lines[i].min_len); } } qsort(lines, line_count, sizeof(*lines), comparator); for (size_t i = 0; i < line_count; i++) { printf("%.4f\t%s\n", lines[i].score, lines[i].line); } freeLineScores(lines, line_count); return 0; }