Add more solutions

Added solutions for problems 36, 37, 38, 39 and 40 in python and C

C/p036.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "projecteuler.h"
+
+int main(int argc, char **argv)
+{
+   int i, sum = 0;
+   double elapsed;
+   struct timespec start, end;
+
+   clock_gettime(CLOCK_MONOTONIC, &start);
+
+   for(i = 1; i < 1000000; i += 2)
+   {
+      if(is_palindrome(i, 10) && is_palindrome(i, 2))
+      {
+         sum += i;
+      }
+   }
+
+   clock_gettime(CLOCK_MONOTONIC, &end);
+
+   elapsed = (end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) / 1000000000;
+
+   printf("Project Euler, Problem 36\n");
+   printf("Answer: %d\n", sum);
+
+   printf("Elapsed time: %.9lf seconds\n", elapsed);
+
+   return 0;
+}

C/p037.c

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+#include "projecteuler.h"
+
+int is_tr_prime(int n);
+
+int main(int argc, char **argv)
+{
+   int i = 0, n = 1, sum = 0;
+   double elapsed;
+   struct timespec start, end;
+
+   clock_gettime(CLOCK_MONOTONIC, &start);
+
+   while(i < 11)
+   {
+      if(is_tr_prime(n))
+      {
+         sum += n;
+         i++;
+      }
+      n++;
+   }
+
+   clock_gettime(CLOCK_MONOTONIC, &end);
+
+   elapsed = (end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) / 1000000000;
+
+   printf("Project Euler, Problem 37\n");
+   printf("Answer: %d\n", sum);
+
+   printf("Elapsed time: %.9lf seconds\n", elapsed);
+
+   return 0;
+}
+
+int is_tr_prime(int n)
+{
+   int i, tmp;
+
+   if(n < 11 || !is_prime(n))
+   {
+      return 0;
+   }
+
+   tmp = n / 10;
+
+   while(tmp > 0)
+   {
+      if(!is_prime(tmp))
+      {
+         return 0;
+      }
+      tmp /= 10;
+   }
+
+   i = 10;
+   tmp = n % i;
+
+   while(tmp != n)
+   {
+      if(!is_prime(tmp))
+      {
+         return 0;
+      }
+      i *= 10;
+      tmp = n % i;
+   }
+
+   return 1;
+}

C/p038.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int is_pandigital(int value, int n);
+
+int main(int argc, char **argv)
+{
+   int i, j, tmp;
+   long int n, max = 0;
+   double elapsed;
+   struct timespec start, end;
+
+   clock_gettime(CLOCK_MONOTONIC, &start);
+
+   for(i = 1; i < 10000; i++)
+   {
+      n = 0;
+      j = 1;
+      do
+      {
+         tmp = i * j;
+         n += tmp;
+         j++;
+
+         if(n > max && is_pandigital(n, 9))
+         {
+            max = n;
+         }
+         if(i * j < 10)
+         {
+            n *= 10;
+         }
+         else if(i * j < 100)
+         {
+            n *= 100;
+         }
+         else if(i * j < 1000)
+         {
+            n *= 1000;
+         }
+         else if(i * j < 10000)
+         {
+            n *= 10000;
+         }
+         else if(i * j < 100000)
+         {
+            n *= 100000;
+         }
+      }while(n <= 987654321);
+   }
+
+   clock_gettime(CLOCK_MONOTONIC, &end);
+
+   elapsed=(end.tv_sec-start.tv_sec)+(double)(end.tv_nsec-start.tv_nsec)/1000000000;
+
+   printf("Project Euler, Problem 38\n");
+   printf("Answer: %ld\n", max);
+
+   printf("Elapsed time: %.9lf seconds\n", elapsed);
+
+   return 0;
+}
+
+int is_pandigital(int value, int n)
+{
+   int *digits;
+   int i, digit;
+
+   if((digits = (int *)calloc(n+1, sizeof(int))) == NULL)
+   {
+      fprintf(stderr, "Error while allocating memory\n");
+      exit(1);
+   }
+
+   for(i = 0; i < n && value > 0; i++)
+   {
+      digit = value % 10;
+      digits[digit]++;
+      value /= 10;
+   }
+
+   if(i < n || value > 0)
+   {
+      free(digits);
+      return 0;
+   }
+
+   if(digits[0] != 0)
+   {
+      free(digits);
+      return 0;
+   }
+
+   for(i = 1; i <= n; i++)
+   {
+      if(digits[i] != 1)
+      {
+         free(digits);
+         return 0;
+      }
+   }
+
+   free(digits);
+
+   return 1;
+}

C/p039.c

@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int main(int argc, char **argv)
+{
+   int p, m, n, a, b, c, count, max = 0, res = 0, tmpa, tmpb, tmpc, i;
+   int savedc[1000] = {0};
+   double elapsed;
+   struct timespec start, end;
+
+   clock_gettime(CLOCK_MONOTONIC, &start);
+
+   for(p = 12; p <= 1000; p++)
+   {
+      count = 0;
+      a = 0;
+      b = 0;
+      c = 0;
+
+      for(m = 2; m * m < p; m++)
+      {
+         for(n = 1; n < m; n++)
+         {
+            a = m * m - n * n;
+            b = 2 * m * n;
+            c = m * m + n * n;
+
+            if(a + b + c == p && !savedc[c])
+            {
+               savedc[c] = 1;
+               count++;
+            }
+
+            i = 2;
+            tmpa = a;
+            tmpb = b;
+            tmpc = c;
+
+            while(tmpa + tmpb + tmpc < p)
+            {
+               tmpa = a * i;
+               tmpb = b * i;
+               tmpc = c * i;
+
+               if(tmpa + tmpb + tmpc == p && !savedc[tmpc])
+               {
+                  savedc[tmpc] = 1;
+                  count++;
+               }
+
+               i++;
+            }
+         }
+      }
+
+      if(count > max)
+      {
+         max = count;
+         res = p;
+      }
+   }
+
+   clock_gettime(CLOCK_MONOTONIC, &end);
+
+   elapsed = (end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) / 1000000000;
+
+   printf("Project Euler, Problem 39\n");
+   printf("Answer: %d\n", res);
+
+   printf("Elapsed time: %.9lf seconds\n", elapsed);
+
+   return 0;
+}

C/p040.c

@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int main(int argc, char **argv)
+{
+   int i, value, n;
+   int digits[1000005];
+   double elapsed;
+   struct timespec start, end;
+   
+   clock_gettime(CLOCK_MONOTONIC, &start);
+
+   i = 1;
+   value = 1;
+
+   while(i <= 1000000)
+   {
+      if(value < 10)
+      {
+         digits[i-1] = value;
+         i++;
+      }
+      else if(value < 100)
+      {
+         digits[i-1] = value / 10;
+         digits[i] = value % 10;
+         i += 2;
+      }
+      else if(value < 1000)
+      {
+         digits[i-1] = value / 100;
+         digits[i] = (value / 10) % 10;
+         digits[i+1] = value % 10;
+         i += 3;
+      }
+      else if(value < 10000)
+      {
+         digits[i-1] = value / 1000;
+         digits[i] = (value / 100) % 10;
+         digits[i+1] = (value / 10) % 10;
+         digits[i+2] = value % 10;
+         i += 4;
+      }
+      else if(value < 100000)
+      {
+         digits[i-1] = value / 10000;
+         digits[i] = (value / 1000) % 10;
+         digits[i+1] = (value / 100) % 10;
+         digits[i+2] = (value / 10) % 10;
+         digits[i+3] = value % 10;
+         i += 5;
+      }
+      else if(value < 1000000)
+      {
+         digits[i-1] = value / 100000;
+         digits[i] = (value / 10000) % 10;
+         digits[i+1] = (value / 1000) % 10;
+         digits[i+2] = (value / 100) % 10;
+         digits[i+3] = (value / 10) % 10;
+         digits[i+4] = value % 10;
+         i += 6;
+      }
+      value++;
+   }
+
+   n = digits[0] * digits[9] * digits[99] * digits[999] * digits[9999] * digits[99999] * digits[999999];
+
+   clock_gettime(CLOCK_MONOTONIC, &end);
+
+   elapsed=(end.tv_sec-start.tv_sec)+(double)(end.tv_nsec-start.tv_nsec)/1000000000;
+
+   printf("Project Euler, Problem 40\n");
+   printf("Answer: %d\n", n);
+
+   printf("Elapsed time: %.9lf seconds\n", elapsed);
+
+   return 0;
+}

Python/p036.py

@@ -0,0 +1,23 @@
+#!/usr/bin/python3
+
+from timeit import default_timer
+from projecteuler import is_palindrome
+
+def main():
+    start = default_timer()
+
+    sum_ = 0
+
+    for i in range(1, 1000000):
+        if is_palindrome(i, 10) and is_palindrome(i, 2):
+            sum_ = sum_ + i
+
+    end = default_timer()
+
+    print('Project Euler, Problem 36')
+    print('Answer: {}'.format(sum_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p037.py

@@ -0,0 +1,49 @@
+#!/usr/bin/python3
+
+from timeit import default_timer
+from projecteuler import is_prime
+
+def is_tr_prime(n):
+    if n < 11 or not is_prime(n):
+        return False
+
+    tmp = n // 10
+
+    while tmp > 0:
+        if not is_prime(tmp):
+            return 0
+        tmp = tmp // 10
+
+    i = 10
+    tmp = n % i
+
+    while tmp != n:
+        if not is_prime(tmp):
+            return 0
+        i = i * 10
+        tmp = n % i
+
+    return 1
+
+def main():
+    start = default_timer()
+
+    i = 0
+    n = 1
+    sum_ = 0
+
+    while i < 11:
+        if is_tr_prime(n):
+            sum_ = sum_ + n
+            i = i + 1
+        n = n + 1
+
+    end = default_timer()
+
+    print('Project Euler, Problem 37')
+    print('Answer: {}'.format(sum_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p038.py

@@ -0,0 +1,69 @@
+#!/usr/bin/python3
+
+from numpy import zeros
+
+from timeit import default_timer
+
+def is_pandigital(value, n):
+    i = 0
+
+    digits = zeros(n + 1, int)
+
+    while i < n and value > 0:
+        digit = value % 10
+        digits[digit] = digits[digit] + 1
+        value = value // 10
+        i = i + 1
+
+    if i < n or value > 0:
+        return 0
+
+    if digits[0] != 0:
+        return 0
+
+    for i in range(1, n+1):
+        if digits[i] != 1:
+            return 0
+        i = i + 1
+
+    return 1
+
+def main():
+    start = default_timer()
+
+    max_ = 0
+
+    for i in range(1, 10000):
+        n = 0
+        j = 1
+
+        while 1:
+            tmp = i * j
+            n = n + tmp
+            j = j + 1
+
+            if n > max_ and is_pandigital(n, 9):
+                max_ = n
+            if i * j < 10:
+                n = n * 10
+            elif i * j < 100:
+                n = n * 100
+            elif i * j < 1000:
+                n = n * 1000
+            elif i * j < 10000:
+                n = n * 10000
+            elif i * j < 100000:
+                n = n * 100000
+
+            if n > 987654321:
+                break
+
+    end = default_timer()
+
+    print('Project Euler, Problem 38')
+    print('Answer: {}'.format(max_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p039.py

@@ -0,0 +1,60 @@
+#!/usr/bin/python3
+
+from numpy import zeros
+
+from timeit import default_timer
+
+def main():
+    start = default_timer()
+
+    max_ = 0
+    savedc = zeros(1000, int)
+
+    for p in range(12, 1001):
+        count = 0
+        a = 0
+        b = 0
+        c = 0
+        m = 2
+
+        while m * m < p:
+            for n in range(1, m):
+                a = m * m - n * n
+                b = 2 * m * n
+                c = m * m + n * n
+
+                if a + b + c == p and savedc[c] == 0:
+                    savedc[c] = 1
+                    count = count + 1
+
+                i = 2
+                tmpa = a
+                tmpb = b
+                tmpc = c
+
+                while tmpa + tmpb + tmpc < p:
+                    tmpa = a * i
+                    tmpb = b * i
+                    tmpc = c * i
+
+                    if tmpa + tmpb + tmpc == p and savedc[tmpc] == 0:
+                        savedc[tmpc] = 1
+                        count = count + 1
+
+                    i = i + 1
+
+            m = m + 1
+
+        if count > max_:
+            max_ = count
+            res = p
+
+    end = default_timer()
+
+    print('Project Euler, Problem 39')
+    print('Answer: {}'.format(res))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p040.py

@@ -0,0 +1,60 @@
+#!/usr/bin/python3
+
+from numpy import zeros
+
+from timeit import default_timer
+
+def main():
+    start = default_timer()
+
+    digits = zeros(1000005, int)
+    i = 1
+    value = 1
+
+    while i <= 1000000:
+        if value < 10:
+            digits[i-1] = value
+            i = i + 1
+        elif value < 100:
+            digits[i-1] = value / 10
+            digits[i] = value % 10
+            i = i + 2
+        elif value < 1000:
+            digits[i-1] = value / 100
+            digits[i] = (value / 10) % 10
+            digits[i+1] = value % 10
+            i = i + 3
+        elif value < 10000:
+            digits[i-1] = value / 1000
+            digits[i] = (value / 100) % 10
+            digits[i+1] = (value / 10) % 10
+            digits[i+2] = value % 10
+            i = i + 4
+        elif value < 100000:
+            digits[i-1] = value / 10000
+            digits[i] = (value / 1000) % 10
+            digits[i+1] = (value / 100) % 10
+            digits[i+2] = (value / 10) % 10
+            digits[i+3] = value % 10
+            i = i + 5
+        elif value < 1000000:
+            digits[i-1] = value / 100000
+            digits[i] = (value / 10000) % 10
+            digits[i+1] = (value / 1000) % 10
+            digits[i+2] = (value / 100) % 10
+            digits[i+3] = (value / 10) % 10
+            digits[i+4] = value % 10
+            i = i + 6
+        value = value + 1
+
+    n = digits[0] * digits[9] * digits[99] * digits[999] * digits[9999] * digits[99999] * digits[999999]
+
+    end = default_timer()
+
+    print('Project Euler, Problem 40')
+    print('Answer: {}'.format(n))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()