hdu4825 01字典树+贪心

来源：互联网发布：centos双系统安装教程编辑：程序博客网时间：2024/05/19 03:21

从高位向低位构造字典树，因为高位得到的数更大。

AC代码：

#include<cstdio>using namespace std;typedef long long LL;const int maxn=2;struct node{node *next[maxn];node(){next[0]=next[1]=NULL;}}*root;LL w[50];void deal(){w[0]=1;for(int i=1;i<=36;++i) w[i]=w[i-1]*2;}void Init(){  root = new node();}void insert_tree(LL num){node *p=root,*q;for(int i=32;i>=0;--i){LL h=num&w[i];int u=0;if(h!=0) u=1;if(p->next[u]==NULL){q=new node();p->next[u]=q;p=p->next[u];}else {p=p->next[u];}}}LL getAns(LL num,node *u,int lev){if(lev<0||u==NULL) return 0;LL ans=0;int h=num&w[lev];if(h!=0) h=1;h=1-h; //xorif(u->next[h]==NULL) ans+=(1-h)*w[lev]+getAns(num,u->next[1-h],lev-1); else ans+=h*w[lev]+getAns(num,u->next[h],lev+-1); return ans;}void free_tree(node *u){ //释放内存 if(u==NULL) return;free_tree(u->next[0]);free_tree(u->next[1]);delete u;}int main(){deal();int T,n,m,kase=1;LL x;scanf("%d",&T);while(T--){Init();scanf("%d%d",&n,&m);for(int i=0;i<n;++i) {scanf("%lld",&x);insert_tree(x);}printf("Case #%d:\n",kase++);LL S;for(int i=0;i<m;++i){scanf("%lld",&S);printf("%lld\n",getAns(S,root,32));}free_tree(root);}return 0;}

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