HDU 1850 Being a Good Boy in Spring Festival
题解:尼姆博弈,SG(i)=i,要使当前堆可取,则数量必须大于其余所有堆的SG异或值,这样才可以减到其SG值使总异或值为0,又不可不取,所以不能取等号。
#include <cstdio> using namespace std; int SG[105]; int main(){ int n,sum,cnt,i; while (scanf("%d",&n),n){ sum=cnt=0; for(i=0;i<n;i++)scanf("%d",&SG[i]),sum^=SG[i]; for(i=0;i<n;i++){sum^=SG[i];if(SG[i]>sum)cnt++;sum^=SG[i];} printf("%d\n",cnt); } return 0; }
愿你出走半生,归来仍是少年