yee

1 files changed, 54 insertions, 0 deletions

diff --git a/2021/07/solve.c b/2021/07/solve.c
new file mode 100644
index 0000000..6e399c9
--- /dev/null
+++ b/2021/07/solve.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define ABS(a) ((a) < 0 ? -(a) : (a))
+
+static void solve(FILE *fp)
+{
+	int crabs[1024] = { 0 };
+	long cnt = 0;
+	char ch;
+	int pos, max = 0;
+	while (fscanf(fp, "%d%c", &pos, &ch) != EOF && (ch == ',' || ch == '\n')) {
+		crabs[cnt++] = pos;
+		if (pos > max)
+			max = pos;
+	}
+
+	int fuel1 = 0xfffffff, fuel2 = fuel1;
+	for (int i = 0; i < max; i++) {
+		int a = 0, b = 0;
+		for (int j = 0; j < cnt; j++) {
+			a += ABS(crabs[j] - i);
+			int d = ABS(crabs[j] - i);
+			b += (d * (d + 1)) / 2;
+		}
+
+		if (a < fuel1)
+			fuel1 = a;
+
+		if (b < fuel2)
+			fuel2 = b;
+	}
+
+	printf("%d\n%d\n", fuel1, fuel2);
+}
+
+int main(int argc, char *argv[])
+{
+	(void)argc;
+	(void)argv;
+
+	FILE *fp = fopen("input", "r");
+	if (!fp)
+		exit(EXIT_FAILURE);
+
+	clock_t tic = clock();
+	solve(fp);
+	clock_t toc = clock();
+	printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
+
+	fclose(fp);
+	return 0;
+}