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eagletmteagletmt
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add problem3[0-9]
1 parent 810601a commit 893224c

10 files changed

+515
-0
lines changed

‎30-39/problem30.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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#include <math.h>
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#define M 1000000
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#define E 5
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int main(void)
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{
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char buf[16];
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int i;
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int ttl = 0;
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for (i = 10; i < M; i++) {
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int sum = 0, j;
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snprintf(buf, sizeof buf, "%d", i);
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for (j = 0; buf[j]; j++) {
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sum += pow(buf[j]-'0', E);
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}
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if (i == sum) {
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ttl += i;
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}
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}
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printf("%d\n", ttl);
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return 0;
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}
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‎30-39/problem31.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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int main(void)
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{
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int z = 0;
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int n = 200;
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int a, b, c, d, e, f, g;
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for (a = 0; a <= n; a += 200)
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for (b = 0; b <= n; b += 100)
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for (c = 0; c <= n; c += 50)
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for (d = 0; d <= n; d += 20)
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for (e = 0; e <= n; e += 10)
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for (f = 0; f <= n; f += 5)
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for (g = 0; g <= n; g += 2)
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if (a+b+c+d+e+f+g <= 200)
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z++;
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printf("%d\n", z);
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return 0;
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}
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‎30-39/problem32.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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static int compare(const void *a, const void *b);
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static int is_pandigital(char *buf);
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#define DIGITS(x) (lround(floor(log10((double)x))))
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int main(void)
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{
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int product, multiplier, multiplicand, remaindar;
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int sum = 0;
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char buf[10];
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for (product = 1111; product < 100000; product++) {
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for (multiplicand = 2; multiplicand*multiplicand < product; multiplicand++) {
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remaindar = product % multiplicand;
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if (remaindar != 0) {
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continue;
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}
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multiplier = product / multiplicand;
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if (DIGITS(multiplicand) + DIGITS(multiplier) + DIGITS(product) != 6) {
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continue;
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}
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snprintf(buf, sizeof buf, "%d%d%d", multiplicand, multiplier, product);
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if (is_pandigital(buf)) {
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sum += product;
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break;
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}
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}
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}
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printf("%d\n", sum);
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return 0;
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}
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static int compare(const void *a, const void *b)
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{
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return *(const char *)a - *(const char *)b;
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}
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static int is_pandigital(char *buf)
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{
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qsort(buf, 9, 1, compare);
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return memcmp(buf, "123456789", 9) == 0;
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}
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‎30-39/problem33.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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#include <math.h>
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static unsigned gcd(unsigned a, unsigned b);
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static int cancel(unsigned n1, unsigned d1, unsigned *n2, unsigned *d2);
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int main(void)
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{
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unsigned ans_n = 1, ans_d = 1;
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unsigned i;
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for (i = 11; i < 100; i++) {
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unsigned j;
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if (i % 10 == 0) {
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continue;
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}
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for (j = 11; j < i; j++) {
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unsigned g, n, d;
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unsigned n2, d2;
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if (j % 10 == 0) {
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continue;
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}
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if ((g = gcd(i, j)) == 1) {
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continue;
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}
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/* cancel numerically */
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n = j/g;
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d = i/g;
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/* cancel symbolically */
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if (cancel(j, i, &n2, &d2)) {
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unsigned g2 = gcd(n2, d2);
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n2 /= g2; d2 /= g2;
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if (n == n2 && d == d2) {
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ans_n *= n;
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ans_d *= d;
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}
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}
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}
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}
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printf("%u\n", ans_d / gcd(ans_n, ans_d));
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return 0;
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}
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unsigned gcd(unsigned a, unsigned b)
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{
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unsigned r;
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while ((r = a % b) != 0) {
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a = b; b = r;
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}
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return b;
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}
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int cancel(unsigned n1, unsigned d1, unsigned *n2, unsigned *d2)
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{
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if (n1%10 == d1%10) {
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/* e.g. 24 and 34 */
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*n2 = n1/10;
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*d2 = d1/10;
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return 1;
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}
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else if (n1%10 == d1/10) {
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/* e.g. 24 and 41 */
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*n2 = n1/10;
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*d2 = d1%10;
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return 1;
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}
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else if (n1/10 == d1%10) {
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/* e.g. 24 and 32 */
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*n2 = n1%10;
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*d2 = d1/10;
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return 1;
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}
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else if (n1/10 == d1/10) {
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/* e.g. 24 and 21 */
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*n2 = n1%10;
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*d2 = d1%10;
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return 1;
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}
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else {
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*n2 = n1;
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*d2 = d1;
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return 0;
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}
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}
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‎30-39/problem34.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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unsigned fact(unsigned n);
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int main(void)
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{
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unsigned i, sum = 0;
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char buf[16];
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for (i = 3; i < 100000; i++) {
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unsigned j, s = 0;
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snprintf(buf, sizeof buf, "%u", i);
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for (j = 0; buf[j] != 0; j++) {
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s += fact(buf[j]-'0');
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}
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if (i == s) {
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sum += s;
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}
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}
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printf("%u\n", sum);
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return 0;
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}
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unsigned fact(unsigned n)
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{
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unsigned f = 1;
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while (n != 0) {
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f *= n--;
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}
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return f;
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}
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‎30-39/problem35.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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#include <math.h>
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#define N 1000000
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static int is_prime(unsigned n);
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int main(void)
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{
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unsigned i, count = 0;
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for (i = 2; i < N; i++) {
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unsigned digits;
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unsigned k;
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unsigned j;
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if (!is_prime(i)) {
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continue;
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}
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digits = log10(i);
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k = i;
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for (j = 0; j < digits; j++) {
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unsigned l = pow(10, digits);
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unsigned t = k % l;
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k /= l;
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k += t*10;
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if (!is_prime(k)) {
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goto NEXT;
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}
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}
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count++;
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NEXT:
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;
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}
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printf("%u\n", count);
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return 0;
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}
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int is_prime(unsigned n)
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{
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if (n <= 1) {
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return 0;
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}
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else if (n == 2) {
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return 1;
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}
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else {
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unsigned i;
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for (i = 2; i*i <= n; i++) {
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if (n % i == 0) {
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return 0;
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}
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}
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return 1;
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}
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}
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‎30-39/problem36.c

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/*
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* Copyright (c) 2009, eagletmt
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* Released under the MIT License <http://opensource.org/licenses/mit-license.php>
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*/
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#include <stdio.h>
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#define N 1000000
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static int palindromic_base(int n, int base);
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int main(void)
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{
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int i;
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int sum = 0;
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for (i = 1; i < N; i++) {
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if (palindromic_base(i, 10) && palindromic_base(i, 2)) {
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sum += i;
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}
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}
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printf("%d\n", sum);
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return 0;
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}
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int palindromic_base(int n, int base)
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{
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int reversed = 0;
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const int orig = n;
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while (n) {
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reversed = base*reversed + n%base;
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n /= base;
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}
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return orig == reversed;
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}
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