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

archives/12/src/main.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include "utils.h"
+
+/*
+The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:
+
+1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
+
+Let us list the factors of the first seven triangle numbers:
+
+ 1: 1
+ 3: 1,3
+ 6: 1,2,3,6
+10: 1,2,5,10
+15: 1,3,5,15
+21: 1,3,7,21
+28: 1,2,4,7,14,28
+We can see that 28 is the first triangle number to have over five divisors.
+
+What is the value of the first triangle number to have over five hundred divisors?
+
+https://projecteuler.net/problem=12
+*/
+
+int main(int argc,char**argv) {
+    int counter=1;
+    long sum=0;
+    while (true) {
+        sum+=counter;
+        printf("Checking %ld...\n",sum);
+        int current=1;
+        int max=sum;
+        int divisorCount=0;
+        while (current<max) {
+            if (max==current&&sum%current==0) {
+                divisorCount++;
+                break;
+            } else
+            if (sum%current==0) {
+                max=sum/current;
+                divisorCount+=2;
+            }
+            current++;
+        }
+        printf(" has %d divisors.\n",divisorCount);
+        if (divisorCount>500) {
+            printf("\n\nNumber %ld has %d divisors!",sum,divisorCount);
+            return 0;
+        }
+        counter++;
+    }
+    return 0;
+}

archives/12/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

@@ -2,86 +2,52 @@
 #include "utils.h"
 
 /*
-In the 20×20 grid below, four numbers along a diagonal line have been marked in red.
+The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:
 
-08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
+1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
-49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
-81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
-52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
-22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
-24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
-32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
-67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
-24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
-21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
-78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
-16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
-86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
-19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
-04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
-88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
-04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
-20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
-20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
-01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48
 
-The product of these numbers is 26 × 63 × 78 × 14 = 1788696.
+Let us list the factors of the first seven triangle numbers:
 
-What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?
+ 1: 1
+ 3: 1,3
+ 6: 1,2,3,6
+10: 1,2,5,10
+15: 1,3,5,15
+21: 1,3,7,21
+28: 1,2,4,7,14,28
+We can see that 28 is the first triangle number to have over five divisors.
 
-https://projecteuler.net/problem=11
+What is the value of the first triangle number to have over five hundred divisors?
-*/
 
-void checkForProduct(int*largestProd,int product) {
+https://projecteuler.net/problem=12
-    if (product>*largestProd) {
+*/
-        *largestProd=product;
-        printf("Largest product is now %d\n",*largestProd);
-    }
-}
 
 int main(int argc,char**argv) {
-
+    int counter=1;
-    int GRID[]={8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8,49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0,81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65,52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91,22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80,24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50,32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70,67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21,24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72,21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95,78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92,16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57,86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58,19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40,4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66,88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69,4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36,20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16,20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54,1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48,};
+    long sum=0;
-
+    while (true) {
-    int largestProd=0;
+        sum+=counter;
-    for (int i=0;i<400;i++) {
+        printf("Checking %ld...\n",sum);
-        int x=i%20;
+        int current=1;
-        int y=i/20;
+        int max=sum;
-        //Up
+        int divisorCount=0;
-        if (y>=3) {
+        while (current<max) {
-            checkForProduct(&largestProd,GRID[(y-3)*20+x]*GRID[(y-2)*20+x]*GRID[(y-1)*20+x]*GRID[i]);
+            if (max==current&&sum%current==0) {
-        }
+                divisorCount++;
-        //Right
+                break;
-        if (x<=16) {
+            } else
-            checkForProduct(&largestProd,GRID[(y)*20+x+1]*GRID[(y)*20+x+2]*GRID[(y)*20+x+3]*GRID[i]);
+            if (sum%current==0) {
-        }
+                max=sum/current;
-        //Left
+                divisorCount+=2;
-        if (x>=3) {
+            }
-            checkForProduct(&largestProd,GRID[(y)*20+x-1]*GRID[(y)*20+x-2]*GRID[(y)*20+x-3]*GRID[i]);
+            current++;
-        }
+        }
-        //Down
+        printf(" has %d divisors.\n",divisorCount);
-        if (y<=16) {
+        if (divisorCount>500) {
-            checkForProduct(&largestProd,GRID[(y+1)*20+x]*GRID[(y+2)*20+x]*GRID[(y+3)*20+x]*GRID[i]);
+            printf("\n\nNumber %ld has %d divisors!",sum,divisorCount);
-        }
+            return 0;
-        //Up-Left
+        }
-        if (y>=3&&x>=3) {
+        counter++;
-            checkForProduct(&largestProd,GRID[(y-3)*20+x-3]*GRID[(y-2)*20+x-2]*GRID[(y-1)*20+x-1]*GRID[i]);
-        }
-        //Up-Right
-        if (y>=3&&x<=16) {
-            checkForProduct(&largestProd,GRID[(y-1)*20+x+1]*GRID[(y-2)*20+x+2]*GRID[(y-3)*20+x+3]*GRID[i]);
-        }
-        //Down-Left
-        if (x>=3&&y<=16) {
-            checkForProduct(&largestProd,GRID[(y+1)*20+x-1]*GRID[(y+2)*20+x-2]*GRID[(y+3)*20+x-3]*GRID[i]);
-        }
-        //Down-Right
-        if (y<=16&&x<=16) {
-            checkForProduct(&largestProd,GRID[(y+1)*20+x+1]*GRID[(y+2)*20+x+2]*GRID[(y+3)*20+x+3]*GRID[i]);
-        }
     }
-
-    printf("Highest product is %d",largestProd);
-    
     return 0;
 }