triple

numbers/octal.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main() {
+	FILE *input = fopen("input.txt","r");
+	unsigned long long int nya;
+	fscanf(input, "%lld\n", &nya);
+	fclose(input);
+	FILE *output = fopen("output.txt","w");
+	fprintf(output, "%llo", nya);
+	fclose(output);
+	return 0;
+}
+

numbers/triple.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <string.h>
+
+int pow_(int x, int y) {
+	if (!y) {
+		return 1;
+	}
+	int res = x;
+	for (int i = 1; i <= y-1; ++i) {
+		res = res*x;
+	}
+	return res;
+}
+int main() {
+	char nya[10000];
+	int res = 0;
+	scanf("%s", nya);
+
+	int len = strlen(nya);
+	for (int i = len-1; i >= 0; --i) {
+		res += (nya[i] - '0') * pow_(3, len-i-1);
+	}
+	printf("%d\n", res);
+
+}
+
+