Problem link : https://projecteuler.net/problem=12
Highly divisible triangular number
Problem 12
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:
What is the value of the first triangle number to have over five hundred divisors?
Solution :
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
Let us list the factors of the first seven triangle numbers:1: 1We can see that 28 is the first triangle number to have over five divisors.
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
What is the value of the first triangle number to have over five hundred divisors?
Solution :
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| #include<stdio.h> | |
| int main() | |
| { | |
| int sum=0,counter=1,i,num; | |
| while(1){ | |
| sum=sum+counter; | |
| counter++; // generate triangle number | |
| num=0; | |
| i=1; | |
| while(i*i<=sum){ | |
| if(sum%i==0){ | |
| num=num+2; | |
| } | |
| i++; | |
| } | |
| if(num>=500) | |
| break; | |
| } | |
| printf("%d",sum); | |
| } // end main | |
