From 99e608427f86453bd51399ce88ca79a69a146860 Mon Sep 17 00:00:00 2001
From: Mistivia <i@mistivia.com>
Date: Sun, 14 Dec 2025 21:48:47 +0800
Subject: day 1 part2

---
 01/Makefile |  8 +++++++-
 01/part2.c  | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 01/part2.c

diff --git a/01/Makefile b/01/Makefile
index 7979cbd..cfcbd94 100644
--- a/01/Makefile
+++ b/01/Makefile
@@ -1,5 +1,11 @@
 part1: part1.c
 	gcc part1.c -o part1
 
+part2: part2.c
+	gcc part2.c -o part2
+
 1: part1
-	cat input | ./part1
\ No newline at end of file
+	cat input | ./part1
+
+2: part2
+	cat input | ./part2
\ No newline at end of file
diff --git a/01/part2.c b/01/part2.c
new file mode 100644
index 0000000..211b1bb
--- /dev/null
+++ b/01/part2.c
@@ -0,0 +1,57 @@
+#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 (val >= 100) {
+            count += val / 100;
+            val = val % 100;
+        }
+        if (negative) val = -val;
+        if (end == line+1) continue;
+        int olddial = dial;
+        dial = dial + val;
+        if (dial >= 100) {
+            count++;
+        }
+        if (olddial > 0 && dial <= 0) {
+            count++;
+        }
+        dial = dial % 100;
+        if (dial < 0) dial += 100;
+    }
+    printf("%d\n", count);
+    return 0;
+}
\ No newline at end of file
-- 
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