Data commit

Task/Levenshtein-distance-Alignment/C/levenshtein-distance-alignment.c

@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct edit_s edit_t, *edit;
+struct edit_s {
+	char c1, c2;
+	int n;
+	edit next;
+};
+
+void leven(char *a, char *b)
+{
+	int i, j, la = strlen(a), lb = strlen(b);
+	edit *tbl = malloc(sizeof(edit) * (1 + la));
+	tbl[0] = calloc((1 + la) * (1 + lb), sizeof(edit_t));
+	for (i = 1; i <= la; i++)
+		tbl[i] = tbl[i-1] + (1+lb);
+
+	for (i = la; i >= 0; i--) {
+		char *aa = a + i;
+		for (j = lb; j >= 0; j--) {
+			char *bb = b + j;
+			if (!*aa && !*bb) continue;
+
+			edit e = &tbl[i][j];
+			edit repl = &tbl[i+1][j+1];
+			edit dela = &tbl[i+1][j];
+			edit delb = &tbl[i][j+1];
+
+			e->c1 = *aa;
+			e->c2 = *bb;
+			if (!*aa) {
+				e->next = delb;
+				e->n = e->next->n + 1;
+				continue;
+			}
+			if (!*bb) {
+				e->next = dela;
+				e->n = e->next->n + 1;
+				continue;
+			}
+
+			e->next = repl;
+			if (*aa == *bb) {
+				e->n = e->next->n;
+				continue;
+			}
+
+			if (e->next->n > delb->n) {
+				e->next = delb;
+				e->c1 = 0;
+			}
+			if (e->next->n > dela->n) {
+				e->next = dela;
+				e->c1 = *aa;
+				e->c2 = 0;
+			}
+			e->n = e->next->n + 1;
+		}
+	}
+
+	edit p = tbl[0];
+	printf("%s -> %s: %d edits\n", a, b, p->n);
+
+	while (p->next) {
+		if (p->c1 == p->c2)
+			printf("%c", p->c1);
+		else {
+			putchar('(');
+			if (p->c1) putchar(p->c1);
+			putchar(',');
+			if (p->c2) putchar(p->c2);
+			putchar(')');
+		}
+
+		p = p->next;
+	}
+	putchar('\n');
+
+	free(tbl[0]);
+	free(tbl);
+}
+
+int main(void)
+{
+	leven("raisethysword", "rosettacode");
+	return 0;
+}