【COGS 1534】 [NEERC 2004]K小数 &&【COGS 930】 [河南省队2012] 找第k小的数 可持久化01Trie

板子题，只是记得负数加fix最方便

#include <cstdio>
const int A=,N=;
namespace FIFO
{
    char ch,B[<<],*S=B,*T=B;
    #define getc() (S==T&&(T=(S=B)+fread(B,1,1<<20,stdin),S==T)?0:*S++)
    #define isd(c) (c>='0'&&c<='9')
    int aa,bb;int F(){
        while(ch=getc(),!isd(ch)&&ch!='-');ch=='-'?aa=bb=:(aa=ch-'',bb=);
        while(ch=getc(),isd(ch))aa=aa*+ch-'';return bb?aa:-aa;
    }
}
#define gi FIFO::F()
struct Trie{
    Trie *ch[];int size;
}*root[N],*null,node[(<<)+];
int n,m,sz=;
int main(){
    freopen("kth.in","r",stdin);freopen("kth.out","w",stdout);
    null=node,null->ch[]=null->ch[]=null,root[]=null;
    n=gi,m=gi;for(register int i=,x;i<=n;i++){
        root[i]=node+sz,sz++,x=gi;register Trie *p=root[i],*last=root[i-];
        for(register int i=A;i>=;i--)
            p->ch[(x>>i)&]=node+sz,sz++,p->ch[((x>>i)&)^]=last->ch[((x>>i)&)^],
            p=p->ch[(x>>i)&],last=last->ch[(x>>i)&],p->size=last->size+;
    }
    register int x,y,k;while(m--){
        x=gi,y=gi,k=gi;register Trie *a=root[x-],*b=root[y];register int ret=;
        for(register int i=A;i>=;i--)
            if(b->ch[]->size-a->ch[]->size>=k)a=a->ch[],b=b->ch[];
            else ret|=(<<i),k-=b->ch[]->size-a->ch[]->size,a=a->ch[],b=b->ch[];
        printf("%d\n",ret);
    }
}

【COGS 930】 [河南省队2012] 找第k小的数

#include <cstdio>
const int A=,N=,fox=;
namespace FIFO
{
    char ch,B[<<],*S=B,*T=B;
    #define getc() (S==T&&(T=(S=B)+fread(B,1,1<<20,stdin),S==T)?0:*S++)
    #define isd(c) (c>='0'&&c<='9')
    int aa,bb;int F(){
        while(ch=getc(),!isd(ch)&&ch!='-');ch=='-'?aa=bb=:(aa=ch-'',bb=);
        while(ch=getc(),isd(ch))aa=aa*+ch-'';return bb?aa:-aa;
    }
}
#define gi FIFO::F()
struct Trie{
    Trie *ch[];int size;
}*root[N],*null,node[(<<)+];
int n,m,sz=;
int main(){
    freopen("kthnumber.in","r",stdin);freopen("kthnumber.out","w",stdout);
    null=node,null->ch[]=null->ch[]=null,root[]=null;
    n=gi,m=gi;for(register int i=,x;i<=n;i++){
        root[i]=node+sz,sz++,x=gi+fox;register Trie *p=root[i],*last=root[i-];
        for(register int i=A;i>=;i--)
            p->ch[(x>>i)&]=node+sz,sz++,p->ch[((x>>i)&)^]=last->ch[((x>>i)&)^],
            p=p->ch[(x>>i)&],last=last->ch[(x>>i)&],p->size=last->size+;
    }
    register int x,y,k;while(m--){
        x=gi,y=gi,k=gi;register Trie *a=root[x-],*b=root[y];register int ret=;
        for(register int i=A;i>=;i--)
            if(b->ch[]->size-a->ch[]->size>=k)a=a->ch[],b=b->ch[];
            else ret|=(<<i),k-=b->ch[]->size-a->ch[]->size,a=a->ch[],b=b->ch[];
        printf("%d\n",ret-fox);
    }
}

【COGS 1534】 [NEERC 2004]K小数