【模板】主席树ｂ(￣▽￣)ｄ

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 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 using namespace std;
 6 int cnt=0,original_value[9000001]={0},a[9000001]={0},root[9000001]={0};
 7 struct node{
 8     int val,l,r;
 9 }tree[9000001];
10 struct Node{
11     int id,val;
12 }original[9000001];
13 int cmp(Node x,Node y){
14     return x.val<y.val;
15 }
16 int build(int x,int l,int r){
17     x=++cnt;
18     if(l==r) return x;
19     int mid=(l+r)/2;
20     tree[x].l=build(0,l,mid);
21     tree[x].r=build(0,mid+1,r);
22     return x;
23 }
24 int New(int x){
25     tree[++cnt]=tree[x];
26     tree[cnt].val=tree[x].val+1;
27     return cnt;
28 }
29 int turn(int x,int pos,int l,int r){
30     x=New(x);
31     if(l==r) return x;
32     int mid=(l+r)/2;
33     if(pos<=mid) tree[x].l=turn(tree[x].l,pos,l,mid);
34     else tree[x].r=turn(tree[x].r,pos,mid+1,r);
35     return x;
36 } 
37 int search(int x,int y,int pos,int l,int r){
38     if(l==r) return l;
39     int mid=(l+r)/2;
40     if(pos<=tree[tree[y].l].val-tree[tree[x].l].val)
41         return search(tree[x].l,tree[y].l,pos,l,mid);
42     else return search(tree[x].r,tree[y].r,pos-(tree[tree[y].l].val-tree[tree[x].l].val),mid+1,r);
43 }
44 int main(){
45     //freopen("P3834_6.in","r",stdin);
46     //freopen("hhh.out","w",stdout);
47     int n,m;
48     scanf("%d%d",&n,&m);
49     for(int i=1;i<=n;i++){
50         scanf("%d",&original[i].val);
51         original[i].id=i; 
52     }
53     sort(original+1,original+n+1,cmp);
54     int N=1;
55     a[original[1].id]=N;
56     original_value[N]=original[1].val;
57     for(int i=2;i<=n;i++){
58         if(original[i].val!=original[i-1].val) N++;
59         original_value[N]=original[i].val;
60         a[original[i].id]=N;
61     }
62     root[0]=build(0,1,N);
63     for(int i=1;i<=n;i++) root[i]=turn(root[i-1],a[i],1,N);
64     while(m--){
65         int L,R,K;
66         scanf("%d%d%d",&L,&R,&K);
67         int ans=original_value[search(root[L-1],root[R],K,1,N)];
68         printf("%d\n",ans);
69     }
70     return 0;
71 }