"POJ2104" k-th number

Ideas

Before you know this problem is used in <del> tears </del> partition tree to write the tat is so complicated I can't read it.

And then the president came to save us. ~\ (≧▽≦)/~

It's been a long time since I learned that the Chairman tree Qaq today, and T and W make me die.

Then we learned the new formulation of discretization, without the need for map.

The basic idea is to open a segment tree for each L of [1,l], recording the number of occurrences of each number in [1,l].

Then l+1 can take advantage of the vast majority of the points, different points to re-open the good.

The query is very good, just like splay.

　　

#include <iostream>#include<cstring>#include<string>#include<cstdio>#include<cstdlib>#include<cmath>#include<algorithm>#include<queue>#include<stack>#include<map>#include<Set>#include<list>#include<vector>#include<ctime>#include<functional>#definePRITNF printf#defineScafn scanf#defineSACNF scanf#definefor (i,j,k) for (int i= (j); i<= (k);(i) + +)#defineClear (a) memset (A,0,sizeof (a))using namespacestd;typedef unsignedintUint;Const intinf=0x3fffffff;Const Doubleeps=1e-Ten;///==============struct declaration==============structnode{Node*lc,*RC; intsum; Node () {LC=rc=null;sum=0;}};///==============var declaration=================Const intmaxn=100010; Node POOR[MAXN* -];inttop=0;//#define NEW (Node) (&poor[++top])intn,m,tot=0, k,v;intA[MAXN],SORTED[MAXN];intId[maxn];map<int,int>Mp; Node*seg_tree[maxn],*NULL;///==============function declaration============voidAdd_seg (Node *&l,node *&r,intLintR);voidQuery (Node *&prev,node *&o,intRank,intLintR);voidUpdate (Node *&o,intLintR);///==============main code=======================intMain () {#definefile__#ifdef file__ freopen ("Input.txt","R", stdin); Freopen ("output.txt","W", stdout);#endif scanf ("%d%d",&n,&m);  for(intI=1; i<=n;i++) {scanf ("%d", A +i); Sorted[i]=A[i]; }   NULL=New(Node); NULL->sum=0,NULL->lc=NULL,NULL->rc=NULL; Sort (Sorted+1, sorted+1+N); Tot=unique (sorted,sorted+1+n)-sorted-1; seg_tree[0]=New(Node);  for(intI=1; i<=n;i++) {Seg_tree[i]=New(Node); K=a[i];v=1; Add_seg (Seg_tree[i-1],seg_tree[i],1, tot); }    while(m--){      intL,R,K;SCANF ("%d%d%d",&l,&r,&j); Query (Seg_tree[l-1],seg_tree[r],k,1, tot); }   return 0;}///================fuction code====================voidAdd_seg (Node *&prev,node *&o,intLintR) {   intM= (l+r) >>1; if(prev==null) prev=NULL; if(o==null) o=New(Node); if(l==r) O->sum=v+prev->sum; Else{      if(sorted[m]>=k) {o->rc=prev->RC; o->lc=New(Node); Add_seg (prev->lc,o->lc,l,m); }        Else{o->lc=prev->LC; o->rc=New(Node); Add_seg (prev->rc,o->rc,m+1, R);   } update (O,L,R); }}voidUpdate (Node *&o,intLintR) {o->sum=0; if(o->lc!=null) o->sum+=o->lc->sum; if(o->rc!=null) o->sum+=o->rc->sum;}voidQuery (Node *&l,node *&r,intRank,intLintR) {   if(L==null) L=NULL; if(R==null) R=NULL; intlsum=0, m= (l+r) >>1; if(l==R) {printf ("%d\n", Sorted[l]); return ; }   if(R->lc!=null) Lsum+=r->lc->sum; if(L->lc!=null) Lsum-=l->lc->sum; if(lsum>=Rank) Query (L->lc,r->lc,rank,l,m); ElseQuery (L->rc,r->rc,rank-lsum,m+1, R);}

POJ2104

"POJ2104" k-th number