1 files changed, 44 insertions, 0 deletions

diff --git a/2023/06/6a.c b/2023/06/6a.c
new file mode 100644
index 0000000..4ce8fd1
--- /dev/null
+++ b/2023/06/6a.c
@@ -0,0 +1,44 @@
+#include <inttypes.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define N 100000
+
+#define MIN(a, b) ((a)<(b)?(a):(b))
+#define MAX(a, b) ((a)>(b)?(a):(b))
+
+bool isnum(char c) { return c >= '0' && c <= '9'; }
+
+int64_t readl(int64_t nums[], char *buf) {
+        int64_t i;
+        for (i = 0; *buf; buf++) {
+                if (!isnum(*buf)) continue;
+                nums[i++] = atoll(buf);
+                while (isnum(*buf)) buf++;
+        }
+        return i;
+}
+
+int main() {
+        char line[N], clean[N];
+        int64_t i, n, p, D, x1, x2, t[N], d[N];
+
+        n = readl(t, fgets(line, N, stdin));
+        readl(d, fgets(line, N, stdin));
+
+        p = 1;
+        for (i = 0; i < n; i++) {
+                D = t[i]*t[i] - 4*d[i];
+                if (D < 0) p = 1;
+                double sq = sqrt(D);
+                x1 = (int64_t)floor((t[i] - sq)/2) + 1;
+                x2 = (int64_t)ceil((t[i] + sq)/2) - 1;
+                p *= x2 - x1 + 1;
+        }
+
+        printf("%" PRId64 "\n", p);
+        return 0;
+}