Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

archives/9/src/main.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include "utils.h"
+
+/*
+A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,
+
+a2 + b2 = c2
+For example, 32 + 42 = 9 + 16 = 25 = 52.
+
+There exists exactly one Pythagorean triplet for which a + b + c = 1000.
+Find the product abc.
+
+https://projecteuler.net/problem=9
+*/
+int main(int argc,char**argv) {
+    int a=1;
+    int b=2;
+    int c=997;
+    int sum=0;
+    for (b=2;b<c;b++) {
+        for (a=1;a<b;a++) {
+            int tempC=1000-a-b;
+            if (a*a+b*b==tempC*tempC) {
+                printf("Pythagorean triplet of %d^2+%d^2=%d^2 works for %d+%d+%d=1000\n",a,b,tempC,a,b,tempC);
+                printf("Product is %d",a*b*tempC);
+                return 0;
+            }
+        }
+    }
+    return 0;
+}

archives/9/src/utils.h

@@ -0,0 +1,7 @@
+#define true 1
+#define false 0
+#define boolean char
+struct String{
+    int length;
+    char*str;
+};

src/main.c

@@ -2,66 +2,30 @@
 #include "utils.h"
 
 /*
-The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832.
+A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,
 
-73167176531330624919225119674426574742355349194934
+a2 + b2 = c2
-96983520312774506326239578318016984801869478851843
+For example, 32 + 42 = 9 + 16 = 25 = 52.
-85861560789112949495459501737958331952853208805511
-12540698747158523863050715693290963295227443043557
-66896648950445244523161731856403098711121722383113
-62229893423380308135336276614282806444486645238749
-30358907296290491560440772390713810515859307960866
-70172427121883998797908792274921901699720888093776
-65727333001053367881220235421809751254540594752243
-52584907711670556013604839586446706324415722155397
-53697817977846174064955149290862569321978468622482
-83972241375657056057490261407972968652414535100474
-82166370484403199890008895243450658541227588666881
-16427171479924442928230863465674813919123162824586
-17866458359124566529476545682848912883142607690042
-24219022671055626321111109370544217506941658960408
-07198403850962455444362981230987879927244284909188
-84580156166097919133875499200524063689912560717606
-05886116467109405077541002256983155200055935729725
-71636269561882670428252483600823257530420752963450
 
-Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
+There exists exactly one Pythagorean triplet for which a + b + c = 1000.
+Find the product abc.
 
-https://projecteuler.net/problem=8
+https://projecteuler.net/problem=9
 */
 int main(int argc,char**argv) {
-    char number[]={
+    int a=1;
-        '7','3','1','6','7','1','7','6','5','3','1','3','3','0','6','2','4','9','1','9','2','2','5','1','1','9','6','7','4','4','2','6','5','7','4','7','4','2','3','5','5','3','4','9','1','9','4','9','3','4',
+    int b=2;
-        '9','6','9','8','3','5','2','0','3','1','2','7','7','4','5','0','6','3','2','6','2','3','9','5','7','8','3','1','8','0','1','6','9','8','4','8','0','1','8','6','9','4','7','8','8','5','1','8','4','3',
+    int c=997;
-        '8','5','8','6','1','5','6','0','7','8','9','1','1','2','9','4','9','4','9','5','4','5','9','5','0','1','7','3','7','9','5','8','3','3','1','9','5','2','8','5','3','2','0','8','8','0','5','5','1','1',
+    int sum=0;
-        '1','2','5','4','0','6','9','8','7','4','7','1','5','8','5','2','3','8','6','3','0','5','0','7','1','5','6','9','3','2','9','0','9','6','3','2','9','5','2','2','7','4','4','3','0','4','3','5','5','7',
+    for (b=2;b<c;b++) {
-        '6','6','8','9','6','6','4','8','9','5','0','4','4','5','2','4','4','5','2','3','1','6','1','7','3','1','8','5','6','4','0','3','0','9','8','7','1','1','1','2','1','7','2','2','3','8','3','1','1','3',
+        for (a=1;a<b;a++) {
-        '6','2','2','2','9','8','9','3','4','2','3','3','8','0','3','0','8','1','3','5','3','3','6','2','7','6','6','1','4','2','8','2','8','0','6','4','4','4','4','8','6','6','4','5','2','3','8','7','4','9',
+            int tempC=1000-a-b;
-        '3','0','3','5','8','9','0','7','2','9','6','2','9','0','4','9','1','5','6','0','4','4','0','7','7','2','3','9','0','7','1','3','8','1','0','5','1','5','8','5','9','3','0','7','9','6','0','8','6','6',
+            if (a*a+b*b==tempC*tempC) {
-        '7','0','1','7','2','4','2','7','1','2','1','8','8','3','9','9','8','7','9','7','9','0','8','7','9','2','2','7','4','9','2','1','9','0','1','6','9','9','7','2','0','8','8','8','0','9','3','7','7','6',
+                printf("Pythagorean triplet of %d^2+%d^2=%d^2 works for %d+%d+%d=1000\n",a,b,tempC,a,b,tempC);
-        '6','5','7','2','7','3','3','3','0','0','1','0','5','3','3','6','7','8','8','1','2','2','0','2','3','5','4','2','1','8','0','9','7','5','1','2','5','4','5','4','0','5','9','4','7','5','2','2','4','3',
+                printf("Product is %d",a*b*tempC);
-        '5','2','5','8','4','9','0','7','7','1','1','6','7','0','5','5','6','0','1','3','6','0','4','8','3','9','5','8','6','4','4','6','7','0','6','3','2','4','4','1','5','7','2','2','1','5','5','3','9','7',
+                return 0;
-        '5','3','6','9','7','8','1','7','9','7','7','8','4','6','1','7','4','0','6','4','9','5','5','1','4','9','2','9','0','8','6','2','5','6','9','3','2','1','9','7','8','4','6','8','6','2','2','4','8','2',
+            }
-        '8','3','9','7','2','2','4','1','3','7','5','6','5','7','0','5','6','0','5','7','4','9','0','2','6','1','4','0','7','9','7','2','9','6','8','6','5','2','4','1','4','5','3','5','1','0','0','4','7','4',
-        '8','2','1','6','6','3','7','0','4','8','4','4','0','3','1','9','9','8','9','0','0','0','8','8','9','5','2','4','3','4','5','0','6','5','8','5','4','1','2','2','7','5','8','8','6','6','6','8','8','1',
-        '1','6','4','2','7','1','7','1','4','7','9','9','2','4','4','4','2','9','2','8','2','3','0','8','6','3','4','6','5','6','7','4','8','1','3','9','1','9','1','2','3','1','6','2','8','2','4','5','8','6',
-        '1','7','8','6','6','4','5','8','3','5','9','1','2','4','5','6','6','5','2','9','4','7','6','5','4','5','6','8','2','8','4','8','9','1','2','8','8','3','1','4','2','6','0','7','6','9','0','0','4','2',
-        '2','4','2','1','9','0','2','2','6','7','1','0','5','5','6','2','6','3','2','1','1','1','1','1','0','9','3','7','0','5','4','4','2','1','7','5','0','6','9','4','1','6','5','8','9','6','0','4','0','8',
-        '0','7','1','9','8','4','0','3','8','5','0','9','6','2','4','5','5','4','4','4','3','6','2','9','8','1','2','3','0','9','8','7','8','7','9','9','2','7','2','4','4','2','8','4','9','0','9','1','8','8',
-        '8','4','5','8','0','1','5','6','1','6','6','0','9','7','9','1','9','1','3','3','8','7','5','4','9','9','2','0','0','5','2','4','0','6','3','6','8','9','9','1','2','5','6','0','7','1','7','6','0','6',
-        '0','5','8','8','6','1','1','6','4','6','7','1','0','9','4','0','5','0','7','7','5','4','1','0','0','2','2','5','6','9','8','3','1','5','5','2','0','0','0','5','5','9','3','5','7','2','9','7','2','5',
-        '7','1','6','3','6','2','6','9','5','6','1','8','8','2','6','7','0','4','2','8','2','5','2','4','8','3','6','0','0','8','2','3','2','5','7','5','3','0','4','2','0','7','5','2','9','6','3','4','5','0',};
-    long largestProduct=0;
-    for (int i=0;i<1000-13;i++) {
-        long product=1;
-        for (int j=0;j<13;j++) {
-            product*=number[i+j]-'0';
-        }
-        if (product>largestProduct) {
-            largestProduct=product;
-            printf("Largest product set to %ld\n",largestProduct);
         }
     }
-    printf("\n%ld",largestProduct);
     return 0;
 }