advent2025

commit 2823dda5cf87d879d93c5ebf26b146dabeca0d48
parent afb256e15a18d1ae501cfb9162adfdea1b8c584e
Author: bsandro <email@bsandro.tech>
Date:   Fri,  5 Dec 2025 08:34:59 +0200

day05

Diffstat:
A
day05.c
 | 
94
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 94 insertions(+), 0 deletions(-)
diff --git a/day05.c b/day05.c
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "cputime.h"
+
+#define LEN(x) (sizeof((x))/sizeof((x)[0]))
+#define BUF_SIZE 40
+#define RANGE_SIZE 188
+
+typedef struct {
+    uint64_t from;
+    uint64_t to;
+} Range;
+
+int add_range(Range ranges[RANGE_SIZE], Range r, int cur) {
+    for (int i=0;i<cur;++i) {
+        if (r.from<=ranges[i].from && r.to>=ranges[i].to) {
+            ranges[i] = r;
+            return cur;
+        }
+        if (r.from>=ranges[i].from && r.from<=ranges[i].to && r.to>ranges[i].to) {
+            ranges[i].to = r.to;
+            return cur;
+        }
+        if (r.to>=ranges[i].from && r.to<=ranges[i].to && r.from<ranges[i].from) {
+            ranges[i].from = r.from;
+            return cur;
+        }
+        if (r.from>=ranges[i].from && r.to<=ranges[i].to) {
+            return cur;
+        }
+    }
+    ranges[cur++] = r;
+    return cur;
+}
+
+uint64_t sum_ranges(Range ranges[RANGE_SIZE], int cnt) {
+    uint64_t sum = 0;
+    for (int i=0;i<cnt;++i) {
+        if (ranges[i].from==0 && ranges[i].from==ranges[i].to) continue;
+        sum += ranges[i].to-ranges[i].from+1;
+    }
+    return sum;
+}
+
+int main(void) {
+    char buf[BUF_SIZE] = {0};
+    bool is_ranges = true;
+    Range ranges[RANGE_SIZE] = {0};
+    int cur_range = 0;
+    int p1 = 0;
+    while (fgets(buf, sizeof(buf), stdin)) {
+        if (is_ranges&&strlen(buf)==1) {
+            is_ranges=false;
+            continue;
+        }
+        if (is_ranges) {
+            Range r = {0};
+            sscanf(buf, "%"PRIu64" - %"PRIu64, &r.from, &r.to);
+            cur_range = add_range(ranges, r, cur_range);
+        } else {
+            uint64_t num = 0;
+            sscanf(buf, "%"PRIu64, &num);
+            for (int i=0;i<RANGE_SIZE;++i) {
+                if (num>=ranges[i].from && num<=ranges[i].to) {
+                    p1++;
+                    break;
+                }
+            }
+        }
+    }
+
+    // fold ranges
+    int cnt = RANGE_SIZE;
+    while (1) {
+        int cur = 0;
+        Range ranges1[RANGE_SIZE] = {0};
+        for (int i=0;i<cnt;++i) {
+            if (ranges[i].from==0&&ranges[i].to==0) continue;
+            cur = add_range(ranges1, ranges[i], cur);
+        }
+        memset(ranges, 0, sizeof(ranges));
+        memcpy(ranges, ranges1, sizeof(ranges1));
+        if (cnt == cur) break;
+        cnt = cur;
+    }
+
+    uint64_t p2 = sum_ranges(ranges, cnt);
+
+    printf("p1: %d, p2: %"PRIu64"\n", p1, p2);
+    return 0;
+}