bzoj 4184: shallot （线段树维护线性基）

Posted 2021-02-08 812-xiao-wen

题面

(solution:)

(code:)

#include<iostream>
#include<cstdio>
#include<iomanip>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<ctime>
#include<cmath>
#include<vector>
#include<queue>
#include<map>
#include<set>

#define ll long long
#define db double
#define inf 0x7fffffff
#define rg register int
#define pb push_back
#define midd int mid=(l+r)>>1
#define klr int k,int l,int r
#define zuo k<<1,l,mid
#define you k<<1|1,mid+1,r

using namespace std;

map<int,int> h;
vector<int> a[500005<<2];

int d[31];
int n,v,sl,sr;
int c[500005];

struct ji{
    int b[31];
    ji(){memset(b,0,sizeof(0));}
    inline void add(int x){
        for(rg i=30;i>=0;--i)
            if(x&d[i]){
                if(b[i])x^=b[i];
                else {b[i]=x;return;}
            }
    }
    inline int ask(){
        int res=0;
        for(rg i=30;i>=0;--i)
            if(b[i]&&!(res&d[i]))res^=b[i];
        return res;
    }
}base;

inline int qr(){
    char ch; int sign=1;
    while((ch=getchar())<'0'||ch>'9')
        if(ch=='-')sign=-1;
    int res=ch^48;
    while((ch=getchar())>='0'&&ch<='9')
        res=res*10+(ch^48);
    return res*sign;
}

inline void add(klr){
    if(sl<=l&&r<=sr){ a[k].pb(-v); return ;}
    midd; if(sl<=mid)add(zuo); if(sr>mid)add(you);
}

inline void dfs(klr,ji t){
    for(rg i=0,j=a[k].size();i<j;++i) t.add(a[k][i]);
    if(l==r){printf("%d
",t.ask());return ;}
    midd; dfs(zuo,t); dfs(you,t);
}

int main(){
    freopen("team.in","r",stdin);
    freopen("team.out","w",stdout);
    n=qr();
    for(rg i=30;i>=0;--i)d[i]=1<<i;
    for(rg i=1;i<=n;++i){
        if((c[i]=v=qr())>=0)h[v]=i;
        else sl=h[-v],h[-v]=0,sr=i-1,add(1,1,n);
    }
    for(rg i=1;i<=n;++i)
        if(c[i]>0&&h[c[i]])
            sl=h[c[i]],sr=n,v=-c[i],add(1,1,n);
    dfs(1,1,n,base);
    return 0;
}