"POJ2104" k-th number chairman tree? Functional line-segment tree? Can I persist a line tree? ...... It's one of them anyway.

Test instructions: Interval static section K large.

Exercises

The line tree can be persisted.

To persist a segment tree:

Basic idea: We maintain the segment tree after inserting each node.

Plain Writing (mle+tle) we copy a segment tree and then insert it for each insertion, which guarantees "persistence."

but obviously, time complexity and spatial complexity are all n^2. 233.

So there's an optimization: we find that only LOGN nodes are changed each time, so we just need to create these points and point to the original version of the node.

Spatial complexity Nlogn.

Then the problem is the interval k large, for the interval [a, b], inserted into the segment tree, the node size-(A-1) Time point size, is obviously [a, b] in this interval after inserting the value of the result, according to this can be queried.

The code is too water, do not understand to see the code yourself.

#include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #define N 101000# Define LOGN 20#define inf 0x3f3f3f3f#define ls s[x].son[0] #define RS s[x].son[1]using namespace Std;int pos[n],n,m;int src [N],rank;int crs[n];struct lsh{int X,id;bool operator < (const LSH &a) Const{return x<a.x;}} Lsh[n];int cnt;struct functional_segment_tree{int son[2];int size,l,r;} s[n*logn];inline void pushup (int x) {s[x].size=s[ls].size+s[rs].size;} int build (int last,int l,int r,int d) {int x=++cnt;s[x].size=s[last].size,s[x].l=l,s[x].r=r;if (l==r) {s[x].size++; return x;} int mid=l+r>>1;if (D&LT;=MID) ls=build (s[last].son[0],l,mid,d), Rs=s[last].son[1];else rs=build (s[last].son[1 ],MID+1,R,D), ls=s[last].son[0];p ushup (x); return x;} void query (int last,int now,int l,int r,int k) {if (l==r) {printf ("%d\n", Crs[l]); return;} int mid=l+r>>1,temp=s[s[now].son[0]].size-s[s[last].son[0]].size;if (temp<k) query (S[last].son[1],s[now] . son[1],mid+1,r,k-temp); else Query (S[laST].SON[0],S[NOW].SON[0],L,MID,K);} int main () {//freopen ("test.in", "R", stdin), int i,a,b,c;scanf ("%d%d", &n,&m), for (i=1;i<=n;i++) scanf ("%d" , &lsh[i].x), Lsh[i].id=i;sort (lsh+1,lsh+n+1); Src[lsh[1].id]=++rank,crs[rank]=lsh[1].x;for (i=2;i<=n;i++) { if (lsh[i].x!=lsh[i-1].x) Crs[++rank]=lsh[i].x;src[lsh[i].id]=rank;} for (i=1;i<=n;i++) Pos[i]=build (Pos[i-1],1,rank,src[i]), while (m--) {scanf ("%d%d%d", &a,&b,&c); query (pos[a-1],pos[b],1,n,c);} return 0;}

"POJ2104" k-th number chairman tree? Functional line-segment tree? Can I persist a line tree? ...... It's one of them anyway.