Project Euler Problem 9: Special Pythagorean triplet

Special Pythagorean triplet

Problem 9

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 whicha + b + c = 1000.
Find the product abc.


C++:

#include <iostream>

using namespace std;

int main()
{
    int n, c;

    // a + b + c = n
    // a^2 + b^2 = c^2
    // a < b < c
    // a + b > c
    // a < n / 3
    // b <= (n - a) / 2
    // c = n - a - b

    while(cin >> n) {
        for(int a=1, maxa=n/3; a<maxa; a++) {
            for(int b=a+1, maxb=(n-a)/2; b<=maxb; b++) {
                c = n - a - b;
                if(a + b <= c)
                    continue;
                if(a * a + b * b == c * c)
                    cout << a * b * c << endl;
            }
        }
    }

    return 0;
}


C++(Truth):

#include <iostream>

using namespace std;

int main()
{
    int s, c;

    while(cin >> s) {
        for(int a=3, maxa=(s-3)/3; a<=maxa; a++) {
            for(int b=a+1, maxb=(s-1-a)/2; b<=maxb; b++) {
                c = s - a - b;
                if(a + b <= c)
                    continue;
                if(a * a + b * b == c * c)
                    cout << a * b * c << endl;
            }
        }
    }

    return 0;
}




posted on 2017-03-20 00:09  海岛Blog  阅读(115)  评论(0编辑  收藏  举报

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