From 02524fae8d6def36070fa99101f5c7e437812dca Mon Sep 17 00:00:00 2001
From: Mart Lubbers <mart@martlubbers.net>
Date: Sun, 5 Dec 2021 12:48:57 +0100
Subject: [PATCH] speed up a bit

---
 05a.c | 20 +++++++++++++-------
 05b.c | 27 +++++++++++++++++----------
 2 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/05a.c b/05a.c
index f8d3421..3e5b008 100644
--- a/05a.c
+++ b/05a.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 
-struct line { int x1; int y1; int x2; int y2; };
+struct line { enum {horz, vert} d; int x1; int y1; int x2; int y2; };
 
 #define max(x, y) ((x)>(y) ? (x) : (y))
 #define min(x, y) ((x)<(y) ? (x) : (y))
@@ -21,6 +21,12 @@ int parse_lines(struct line lines[], int *maxx, int *maxy)
 		lines[i].x2 = strtol(p, &p, 10);
 		p++;
 		lines[i].y2 = strtol(p, &p, 10);
+		if (lines[i].x1 == lines[i].x2)
+			lines[i].d = vert;
+		else if (lines[i].y1 == lines[i].y2)
+			lines[i].d = horz;
+		else
+			continue;
 		*maxx = max(*maxx, lines[i].x1);
 		*maxx = max(*maxx, lines[i].x2);
 		*maxy = max(*maxy, lines[i].y1);
@@ -32,12 +38,12 @@ int parse_lines(struct line lines[], int *maxx, int *maxy)
 
 bool online(int x, int y, struct line line)
 {
-	//Vertical
-	if (line.x1 == line.x2 && x == line.x1)
-		return between(y, line.y1, line.y2);
-	//Horizontal
-	if (line.y1 == line.y2 && y == line.y2)
-		return between(x, line.x1, line.x2);
+	switch (line.d) {
+	case vert:
+		return x == line.x1 && between(y, line.y1, line.y2);
+	case horz:
+		return y == line.y1 && between(x, line.x1, line.x2);
+	}
 	return false;
 }
 
diff --git a/05b.c b/05b.c
index d7ca591..208f870 100644
--- a/05b.c
+++ b/05b.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 
-struct line { int x1; int y1; int x2; int y2; };
+struct line { enum {horz, vert, diag} d; int x1; int y1; int x2; int y2; };
 
 #define max(x, y) ((x)>(y) ? (x) : (y))
 #define min(x, y) ((x)<(y) ? (x) : (y))
@@ -21,6 +21,14 @@ int parse_lines(struct line lines[], int *maxx, int *maxy)
 		lines[i].x2 = strtol(p, &p, 10);
 		p++;
 		lines[i].y2 = strtol(p, &p, 10);
+		if (lines[i].x1 == lines[i].x2)
+			lines[i].d = vert;
+		else if (lines[i].y1 == lines[i].y2)
+			lines[i].d = horz;
+		else if (abs(lines[i].y2-lines[i].y1) == abs(lines[i].x2-lines[i].x1))
+			lines[i].d = diag;
+		else
+			continue;
 		*maxx = max(*maxx, lines[i].x1);
 		*maxx = max(*maxx, lines[i].x2);
 		*maxy = max(*maxy, lines[i].y1);
@@ -32,15 +40,14 @@ int parse_lines(struct line lines[], int *maxx, int *maxy)
 
 bool online(int x, int y, struct line line)
 {
-	//Vertical
-	if (line.x1 == line.x2 && x == line.x1)
-		return between(y, line.y1, line.y2);
-	//Horizontal
-	if (line.y1 == line.y2 && y == line.y2)
-		return between(x, line.x1, line.x2);
-	//Diagonal
-	if (abs(line.y2-line.y1) == abs(line.x2-line.x1)) {
-		int slope = (line.y2 - line.y1) / (line.x2 - line.x1);
+	int slope;
+	switch (line.d) {
+	case horz:
+		return y == line.y1 && between(x, line.x1, line.x2);
+	case vert:
+		return x == line.x1 && between(y, line.y1, line.y2);
+	case diag:
+		slope = (line.y2 - line.y1) / (line.x2 - line.x1);
 		return y-line.y1 == slope*(x-line.x1)
 			&& between(y, line.y1, line.y2) && between(x, line.x1, line.x2);
 	}
-- 
2.20.1