uva10790:http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1731
题意：两条水平线，分别有n,m个点，点之间两两连线，求有多少个交点。
题解：手动模拟一下，然后用不完全归纳法，就可以得到公式ans=(n-1)*n/2*(m-1)*m/2;
1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<cstring> 5 using namespace std; 6 long long m, n; 7 int main(){ 8 int tt=1; 9 while(~scanf("%lld%lld",&n,&m)){ 10 if(n==0&&m==0)break; 11 printf("Case %d: %lld\n",tt++,(n-1)*n/2*(m-1)*(m)/2); 12 } 13 }
How Many Points of Intersection?,布布扣,bubuko.com
How Many Points of Intersection?
原文：http://www.cnblogs.com/chujian123/p/3845130.html
