UVa 11417 - GCD

题目：gcd求和。

分析：简单题、数论。打表输出即可。

#include <stdio.h>#include <stdlib.h>#include <string.h>int gcd( int a, int b ){return a%b?gcd(b,a%b):b;}int F[510]; int main(){int sum = 0;for ( int i = 1 ; i <= 500 ; ++ i ) {for ( int j = 1 ; j < i ; ++ j )sum += gcd( j, i );F[i] = sum;}int n; while ( scanf("%d",&n) && n ) printf("%d\n",F[n]);return 0;}