From aa9724dfbf5895c8d2f5b8d605a76a3517a2021b Mon Sep 17 00:00:00 2001
From: Mart Lubbers <mart@martlubbers.net>
Date: Fri, 17 Dec 2021 09:38:53 +0100
Subject: [PATCH] cleanup part one and do part two

---
 17a.c | 31 ++++++-------------------------
 17b.c | 27 +++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 25 deletions(-)
 create mode 100644 17b.c

diff --git a/17a.c b/17a.c
index 2140026..903978e 100644
--- a/17a.c
+++ b/17a.c
@@ -1,21 +1,17 @@
 #include <stdio.h>
-#include <stdlib.h>
 #include <stdbool.h>
-#include <string.h>
 
 bool is_in(int dx, int dy, int x1, int x2, int y1, int y2, int *maxy)
 {
 	int x = 0, y = 0, my = 0;
-	while (y >= y2 && x <= x2) {
+	while (y >= y1 && x <= x2) {
 		x+=dx;
 		y+=dy;
+		my = y > my ? y : my;
 		dx = dx == 0 ? 0 : dx-1;
 		dy--;
-		if (y > my)
-			my = y;
-		if (x >= x1 && x <= x2 && y >= y1 && y <= y2)  {
-			if (my > *maxy)
-				*maxy = my;
+		if (x >= x1 && x <= x2 && y >= y1 && y <= y2) {
+			*maxy = my > *maxy ? my : *maxy;
 			return true;
 		}
 	}
@@ -24,23 +20,8 @@ bool is_in(int dx, int dy, int x1, int x2, int y1, int y2, int *maxy)
 
 int main()
 {
-	size_t len;
-	char *buf = NULL;
-	if (getline(&buf, &len, stdin) == -1)
-		return 1;
-	printf("%s", buf);
-
-	while (*buf++ != '=');
-
-	int x1 = strtol(buf, &buf, 10);
-	buf+=strlen("..");
-	int x2 = strtol(buf, &buf, 10);
-	buf+=strlen(", y=");
-	int y1 = strtol(buf, &buf, 10);
-	buf+=strlen("..");
-	int y2 = strtol(buf, &buf, 10);
-
-	int maxy = 0;
+	int x1, x2, y1, y2, maxy = 0;
+	scanf("target area: x=%d..%d, y=%d..%d\n", &x1, &x2, &y1, &y2);
 	for (int dy = x2; dy >= 0; dy--)
 		for (int dx = 1; dx <= x2; dx++)
 			if (is_in(dx, dy, x1, x2, y1, y2, &maxy))
diff --git a/17b.c b/17b.c
new file mode 100644
index 0000000..a90c27f
--- /dev/null
+++ b/17b.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+bool is_in(int dx, int dy, int x1, int x2, int y1, int y2)
+{
+	int x = 0, y = 0;
+	while (y >= y1 && x <= x2) {
+		x+=dx;
+		y+=dy;
+		dx = dx == 0 ? 0 : dx-1;
+		dy--;
+		if (x >= x1 && x <= x2 && y >= y1 && y <= y2)
+			return true;
+	}
+	return false;
+}
+
+int main()
+{
+	int x1, x2, y1, y2, n = 0;
+	scanf("target area: x=%d..%d, y=%d..%d\n", &x1, &x2, &y1, &y2);
+	for (int dy = x2; dy >= y1; dy--)
+		for (int dx = 0; dx <= x2; dx++)
+			if (is_in(dx, dy, x1, x2, y1, y2))
+				n++;
+	printf("%d\n", n);
+}
-- 
2.20.1