Initial data commit

Task/Shortest-common-supersequence/C/shortest-common-supersequence.c

@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <string.h>
+
+typedef struct link link_t;
+struct link {
+	int len;
+	char letter;
+	link_t *next;
+};
+
+// Stores a copy of a SCS of x and y in out.  Caller needs to make sure out is long enough.
+int scs(char *x, char *y, char *out)
+{
+	int lx = strlen(x), ly = strlen(y);
+	link_t lnk[ly + 1][lx + 1];
+	
+	for (int i = 0; i < ly; i++)
+		lnk[i][lx] = (link_t) {ly - i, y[i], &lnk[i + 1][lx]};
+
+	for (int j = 0; j < lx; j++)
+		lnk[ly][j] = (link_t) {lx - j, x[j], &lnk[ly][j + 1]};
+
+	lnk[ly][lx] = (link_t) {0};
+
+	for (int i = ly; i--; ) {
+		for (int j = lx; j--; ) {
+			link_t *lp = &lnk[i][j];
+			if (y[i] == x[j]) {
+				lp->next = &lnk[i+1][j+1];
+				lp->letter = x[j];
+			} else if (lnk[i][j+1].len < lnk[i+1][j].len) {
+				lp->next = &lnk[i][j+1];
+				lp->letter = x[j];
+			} else {
+				lp->next = &lnk[i+1][j];
+				lp->letter = y[i];
+			}
+			lp->len = lp->next->len + 1;
+		}
+	}
+
+	for (link_t *lp = &lnk[0][0]; lp; lp = lp->next)
+		*out++ = lp->letter;
+
+	return 0;
+}
+
+int main(void)
+{
+	char x[] = "abcbdab", y[] = "bdcaba", res[128];
+	scs(x, y, res);
+	printf("SCS(%s, %s) -> %s\n", x, y, res);
+	return 0;
+}