1 files changed, 69 insertions, 22 deletions

diff --git a/20.c b/20.c
index e738d9c..e427217 100644
--- a/20.c
+++ b/20.c
@@ -2,11 +2,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 
 struct num {
-	int val;
-	int ord;
+	long val;
+	long ord;
 };
 
 
@@ -17,11 +18,54 @@ struct num {
 
 
 int
-main()
+main(int argc, char ** argv)
 {
+	long key = 1, rounds = 1;
 	char buf[BUFSIZ];
 	struct num * nums = NULL;
-	int nnums = 0, numsize = 0, i, pos;
+	int nnums = 0, numsize = 0, r, i, pos;
+
+	// Parse options
+	while ((i = getopt(argc, argv, "p:k:r:")) != -1) {
+		switch (i) {
+		case 'p':
+			switch (atoi(optarg)) {
+			case 1:
+				key = 1;
+				rounds = 1;
+				break;
+
+			case 2:
+				key = 811589153;
+				rounds = 10;
+				break;
+
+			default:
+				fprintf(stderr, "Invalid part %s\n", optarg);
+				return -1;
+			}
+			break;
+
+		case 'k':
+			key = atoi(optarg);
+			if (!key) {
+				fprintf(stderr, "Invalid key %s\n", optarg);
+				return -1;
+			}
+			break;
+
+		case 'r':
+			rounds = atoi(optarg);
+			if (rounds < 0) {
+				fprintf(stderr, "Invalid rounds %s\n", optarg);
+				return -1;
+			}
+			break;
+
+		default:
+			return -1;
+		}
+	}
 
 	// Read file.
 	while (fgets(buf, sizeof(buf), stdin)) {
@@ -46,33 +90,36 @@ main()
 			free(nums);
 			return -1;
 		}
+		nums[nnums].val *= key;
 		nums[nnums].ord = nnums;
 		++nnums;
 	}
 
 	// Mix file.
-	for (i = 0, pos = 0; i < nnums; ++i) {
-		int newpos;
-		struct num tmp;
+	for (r = 0; r < rounds; ++r) {
+		for (i = 0, pos = 0; i < nnums; ++i) {
+			int newpos;
+			struct num tmp;
 
-		// Look for the num whose ordinal is i, starting from the
-		// position of the last num we looked at.
-		while (nums[pos].ord != i)
-			pos = modulo(pos + 1, nnums);
+			// Look for the num whose ordinal is i, starting from the
+			// position of the last num we looked at.
+			while (nums[pos].ord != i)
+				pos = modulo(pos + 1, nnums);
 
-		if (nums[pos].val == 0)
-			continue;
+			if (nums[pos].val == 0)
+				continue;
 
-		// Move this.
-		tmp = nums[pos];
+			// Move this.
+			tmp = nums[pos];
 
-		newpos = modulo(pos + nums[pos].val, nnums - 1); // Buffer of nums does not include moving num
-		if (newpos > pos)
-			memmove(nums + pos, nums + pos + 1, (newpos - pos) * sizeof(struct num));
-		else
-			memmove(nums + newpos + 1, nums + newpos, (pos - newpos) * sizeof(struct num));
+			newpos = modulo(pos + nums[pos].val, nnums - 1); // Buffer of nums does not include moving num
+			if (newpos > pos)
+				memmove(nums + pos, nums + pos + 1, (newpos - pos) * sizeof(struct num));
+			else
+				memmove(nums + newpos + 1, nums + newpos, (pos - newpos) * sizeof(struct num));
 
-		nums[newpos] = tmp;
+			nums[newpos] = tmp;
+		}
 	}
 
 	// Find zero.
@@ -85,7 +132,7 @@ main()
 		return -1;
 	}
 
-	printf("Coords: %d,%d,%d; sum %d\n",
+	printf("Coords: %ld,%ld,%ld; sum %ld\n",
 			nums[modulo(i + 1000, nnums)].val,
 			nums[modulo(i + 2000, nnums)].val,
 			nums[modulo(i + 3000, nnums)].val,