Prepared removing ipython.

other/e030.c

@@ -0,0 +1,81 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdbool.h>
+
+#define DIGITS (6)
+#define BASE_TEN (100000)
+
+uint32_t* get_digits(uint32_t n) {
+    uint32_t* r = malloc(sizeof(uint32_t) * DIGITS);
+	uint32_t base = BASE_TEN;
+	for (size_t i = 0; i < DIGITS; i++) {
+		r[i] = n / base;
+		n = n % base;
+		base /= 10;
+	}
+	return r;
+
+}
+
+uint32_t* get_power_four_lookup() {
+	uint32_t* r = malloc(sizeof(uint32_t) * 10);
+	r[0] = 0;
+	r[1] = 1;
+	r[2] = 2 * 2 * 2 * 2;
+	r[3] = 3 * 3 * 3 * 3;
+	r[4] = 4 * 4 * 4 * 4;
+	r[5] = 5 * 5 * 5 * 5;
+	r[6] = 6 * 6 * 6 * 6;
+	r[7] = 7 * 7 * 7 * 7;
+	r[8] = 8 * 8 * 8 * 8;
+	r[9] = 9 * 9 * 9 * 9;
+	return r;
+}
+
+uint32_t* get_power_five_lookup() {
+	uint32_t* r = malloc(sizeof(uint32_t) * 10);
+	r[0] = 0;
+	r[1] = 1;
+	r[2] = 2 * 2 * 2 * 2 * 2;
+	r[3] = 3 * 3 * 3 * 3 * 3;
+	r[4] = 4 * 4 * 4 * 4 * 4;
+	r[5] = 5 * 5 * 5 * 5 * 5;
+	r[6] = 6 * 6 * 6 * 6 * 6;
+	r[7] = 7 * 7 * 7 * 7 * 7;
+	r[8] = 8 * 8 * 8 * 8 * 8;
+	r[9] = 9 * 9 * 9 * 9 * 9;
+	return r;
+}
+
+bool is_representable(uint32_t number, uint32_t* lookup) {
+	uint32_t* digits = get_digits(number);
+	uint32_t digit_sum = 0;
+	for (size_t i = 0; i < DIGITS; i++)
+		digit_sum += lookup[digits[i]];
+	free(digits);
+	if (number == digit_sum)
+		return true;
+	return false;
+
+}
+
+void print_digits(uint32_t* digits) {
+	for (size_t i = 0; i < DIGITS; i++) {
+		printf("%u", digits[i]);
+	}
+}
+
+int main(int argn, char** argv) {
+	uint32_t* lookup = get_power_five_lookup();
+	uint32_t sum = 0;
+	for (uint32_t n = 10; n < 300000; n++)
+	if (is_representable(n, lookup)) {
+		printf("%u\n", n);
+		sum += n;
+	}
+	printf("Sum: %d\n", sum);
+	free(lookup);
+    return 0;
+}
+