cogs2554 [福利]可持久化线段树

cogs2554 [福利]可持久化线段树

原题链接

每次修改复制一遍就行了。。。
1A！！！

// It is made by XZZ
#include<cstdio>
#include<algorithm>
#define Fname "longterm_segtree"
using namespace std;
#define rep(a,b,c) for(rg int a=b;a<=c;a++)
#define drep(a,b,c) for(rg int a=b;a>=c;a--)
#define erep(a,b) for(rg int a=fir[b];a;a=nxt[a])
#define il inline
#define rg register
#define vd void
#define mid ((l+r)>>1)
typedef long long ll;
il int gi(){
    rg int x=0,f=1;rg char ch=getchar();
    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();
    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
    return x*f;
}
typedef struct node* point;
struct node{
    int max;
    point ls,rs;
    node(int _max){max=_max,ls=rs=NULL;}
};
point root[100001];
int num[10001];
point build(int l,int r){
    point now=new node(19260817);
    if(l==r)now->max=num[l];
    else now->ls=build(l,mid),now->rs=build(mid+1,r),now->max=max(now->ls->max,now->rs->max);
    return now;
}
il int Max(point now,int l,int r,int ll,int rr){
    if(ll<=l&&r<=rr)return now->max;
    if(mid<rr)
	if(mid+1>ll)return max(Max(now->ls,l,mid,ll,rr),Max(now->rs,mid+1,r,ll,rr));
	else return Max(now->rs,mid+1,r,ll,rr);
    else return Max(now->ls,l,mid,ll,rr);
}
il vd Update(point&now,point fr,int l,int r,int pos,int num){
    now=new node(19260817),*now=*fr;
    if(l==r){now->max=num;return;}
    if(pos<=mid)Update(now->ls,fr->ls,l,mid,pos,num);
    else Update(now->rs,fr->rs,mid+1,r,pos,num);
    now->max=max(now->ls->max,now->rs->max);
}
int main(){
    freopen(Fname".in","r",stdin);
    freopen(Fname".out","w",stdout);
    int n=gi(),q=gi(),cnt=0;
    rep(i,1,n)num[i]=gi();
    root[++cnt]=build(1,n);
    int opt;
    int k,a,b;
    while(q--){
	opt=gi();
	k=gi(),a=gi(),b=gi();
	if(opt==0)printf("%d\n",Max(root[k],1,n,a,b));
	else Update(root[++cnt],root[k],1,n,a,b);
    }
    return 0;
}

好慢mdzz。。。