From 68c9a7d1ba2f11897c15494b605d53791e07738f Mon Sep 17 00:00:00 2001
From: Mistivia <i@mistivia.com>
Date: Sun, 14 Dec 2025 21:39:29 +0800
Subject: day 1 part1

---
 .gitignore  |  3 +++
 01/Makefile |  5 +++++
 01/part1.c  | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 01/Makefile
 create mode 100644 01/part1.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..9e38fd5
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+part1
+part2
+input
\ No newline at end of file
diff --git a/01/Makefile b/01/Makefile
new file mode 100644
index 0000000..7979cbd
--- /dev/null
+++ b/01/Makefile
@@ -0,0 +1,5 @@
+part1: part1.c
+	gcc part1.c -o part1
+
+1: part1
+	cat input | ./part1
\ No newline at end of file
diff --git a/01/part1.c b/01/part1.c
new file mode 100644
index 0000000..9777645
--- /dev/null
+++ b/01/part1.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+char buf[1024];
+
+char * readline() {
+    int i = 0;
+    int c;
+    while (1) {
+        c = fgetc(stdin);
+        if (c == EOF) {
+            if (i == 0) {
+                return NULL;
+            }
+            goto end;
+        }
+        if (c == '\n') {
+            goto end;
+        }
+        buf[i] = c;
+        i++;
+    }
+end:
+    buf[i] = '\0';
+    return strdup(buf);
+}
+
+int main() {
+    int dial = 50;
+    char *line;
+    int count = 0;
+    while ((line = readline()) != NULL) {
+        int negative = 0;
+        if (line[0] == 'L') negative = 1;
+        char *end;
+        long val = strtol(line+1, &end, 10);
+        if (negative) val = -val;
+        if (end == line+1) continue;
+        dial = (dial + val) % 100;
+        if (dial < 0) dial += 100;
+        if (dial == 0) count++;
+    }
+    printf("%d\n", count);
+    return 0;
+}
\ No newline at end of file
-- 
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