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主席树
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| #include<iostream> | |
| #include<cstdio> | |
| #include<cstring> | |
| #include<algorithm> | |
| using namespace std; | |
| #define NN 101000 | |
| int n,m,i,ord[NN],b[NN],totn,tott,root[NN],a,bb,c; | |
| struct segtree{ | |
| int ls,rs,l,r,w; | |
| }t[NN*20]; | |
| int bsch(int x,int l,int r){ | |
| int mid; | |
| while(l<=r){ | |
| mid=(l+r)>>1; | |
| if (x==b[mid]) return mid; | |
| else if(b[mid]>x) r=mid-1; | |
| else l=mid+1; | |
| } | |
| printf("fuck!\n"); | |
| } | |
| int build(int l,int r){ | |
| int now=++tott; | |
| t[now].l=l;t[now].r=r;t[now].w=0; | |
| if (l==r){ | |
| t[now].ls=t[now].rs=0;return now; | |
| } | |
| int mid=(l+r)>>1; | |
| t[now].ls=build(l,mid); | |
| t[now].rs=build(mid+1,r); | |
| return now; | |
| } | |
| int insert(int pos,int num,int pas){ | |
| int now=++tott; | |
| t[now]=t[pas]; | |
| t[now].w+=num; | |
| if (t[now].ls==t[now].rs) return now; | |
| int mid=(t[now].l+t[now].r)>>1; | |
| if (pos<=mid) t[now].ls=insert(pos,num,t[now].ls); | |
| else t[now].rs=insert(pos,num,t[now].rs); | |
| return now; | |
| } | |
| int query(int k,int t1,int t2){ | |
| if (t[t1].l==t[t1].r) return t[t1].l; | |
| int tmp; | |
| if ((tmp=t[t[t2].ls].w-t[t[t1].ls].w)>=k){ | |
| return query(k,t[t1].ls,t[t2].ls); | |
| } | |
| else { | |
| return query(k-tmp,t[t1].rs,t[t2].rs); | |
| } | |
| } | |
| inline bool cmp(int x,int y){return x<y;} | |
| int main(){ | |
| scanf("%d%d",&n,&m); | |
| for(i=1;i<=n;i++){scanf("%d",&ord[i]);b[i]=ord[i];} | |
| sort(b+1,b+n+1,cmp); | |
| totn=1; | |
| for(i=2;i<=n;i++){if (b[i]!=b[i-1]) b[++totn]=b[i];} | |
| for(i=1;i<=n;i++){ord[i]=bsch(ord[i],1,totn);} | |
| tott=0; | |
| root[0]=build(1,totn); | |
| for(i=1;i<=n;i++){ | |
| root[i]=insert(ord[i],1,root[i-1]); | |
| } | |
| for(i=1;i<=m;i++){ | |
| scanf("%d%d%d",&a,&bb,&c); | |
| printf("%d\n",b[query(c,root[a-1],root[bb])]); | |
| } | |
| return 0; | |
| } | |
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