模板 可持久化线段树

只支持单点修改区间查值的可持久化线段树

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 struct tree{
 6     int ls;
 7     int rs;
 8     int l,r;
 9     int vls;
10 }tr[10000000];
11 int size;
12 int line[1000000];
13 int n,q;
14 int rt[1000000];
15 int ts;
16 void pushup(int spc)
17 {
18     tr[spc].vls=max(tr[tr[spc].ls].vls,tr[tr[spc].rs].vls);
19 }
20 void build(int &spc,int l,int r)
21 {
22     if(!spc)
23     {
24         spc=++size;
25     }
26     tr[spc].l=l;
27     tr[spc].r=r;
28     if(l==r)
29     {
30         tr[spc].vls=line[l];
31         return ;
32     }
33     int mid=(l+r)>>1;
34     build(tr[spc].ls,l,mid);
35     build(tr[spc].rs,mid+1,r);
36     pushup(spc);
37 }
38 void updt(int &spc,int lst,int plc,int vl)
39 {
40     spc=++size;
41     tr[spc].ls=tr[lst].ls;
42     tr[spc].rs=tr[lst].rs;
43     tr[spc].l=tr[lst].l;
44     tr[spc].r=tr[lst].r;
45     tr[spc].vls=tr[lst].vls;
46     if(tr[spc].l==tr[spc].r)
47     {
48         tr[spc].vls=vl;
49         return ;
50     }
51     if(((tr[spc].l+tr[spc].r)/2)>=plc)
52     {
53         updt(tr[spc].ls,tr[lst].ls,plc,vl);
54     }else{
55         updt(tr[spc].rs,tr[lst].rs,plc,vl);
56     }
57     pushup(spc);
58 }
59 int ask(int l,int r,int spc)
60 {
61     if(tr[spc].l>r||tr[spc].r<l)return -1;
62     if(tr[spc].l>=l&&tr[spc].r<=r)return tr[spc].vls;
63     return max(ask(l,r,tr[spc].ls),ask(l,r,tr[spc].rs));
64 }
65 int main()
66 {
67     scanf("%d%d",&n,&q);
68     for(int i=1;i<=n;i++)
69     {
70         scanf("%d",line+i);
71     }
72     build(rt[++ts],1,n);
73     while(q--)
74     {
75         int cmd,k,lp,rv;
76         scanf("%d%d%d%d",&cmd,&k,&lp,&rv);
77         if(cmd)
78         {
79             updt(rt[++ts],rt[k],lp,rv);
80         }else{
81             printf("%d\n",ask(lp,rv,rt[k]));
82         }
83     }
84     return 0;
85 }