学步园

TAG 数论

简单的数学题。设 n+.. +(n+k)=X， n>0,k>0

有 (2n+k)(k+1)=2X

         k(k+1)   <2X

                k^2<2X

                    k<sqrt(2X)

枚举k到sqrt(2X)就行了

/* source code of submission 421009, Zhongshan University Online Judge System */<br /> #include <stdio.h><br /> #include <math.h><br /> int T;<br /> int no,n;<br /> int cal(int n)<br /> {<br /> int ret=0;<br /> for (int i=1; i<=int( sqrt(2.0)*sqrt(n+0.0) ); ++i)<br /> {<br /> if ( (2*n)%(i+1)==0 && (2*n/(i+1)-i) >=2 && (2*n/(i+1)-i)%2==0 )<br /> {<br /> ++ret;<br /> }<br /> }<br /> return ret;<br /> }<br /> int main(int argc, char *argv[])<br /> {<br /> scanf("%d", &T);<br /> while ( T-- )<br /> {<br /> scanf("%d%d", &no, &n);<br /> printf("%d %d/n",no, cal(n) );<br /> }<br /> return 0;<br /> }<br />