poj 2761 Feed the dogs

原题链接：http://poj.org/problem?id=2761

Treap的做法。具体实现如下：

#include <stdio.h>  #include <stdlib.h>  #include <string.h>  #define N 50020  #define Max_N 100020  #define A_Seed 16807  #define INF 0x7fffffff  #define Q_Seed (INF / A_Seed)  #define R_Seed (INF % A_Seed)  #define node_size(x) (((x)==NULL) ? 0 : ((x)->size))  typedef struct node_t{ int left,right,k,id,ans; }node;  node rec[N];  typedef struct treap_t{      int pretty,fix,size;      struct treap_t *left,*right;  }treap,*Treap;  treap _treap[Max_N<<2];  int sz,pair[Max_N];  static int seed=1;  int Redom(){      int hi=seed / Q_Seed;      int lo=seed % Q_Seed;      int temp = A_Seed * lo - R_Seed * hi;      return temp > 0 ? (seed = temp) : (seed = temp + INF);  }  void rotate_right(Treap *T){      Treap k=(*T)->left;      (*T)->left=k->right;      k->right=*T;      (*T)->size=node_size((*T)->left)+node_size((*T)->right)+1;      k->size=node_size(k->left)+node_size(k->right)+1;      *T=k;  }  void rotate_left(Treap *T){      Treap k=(*T)->right;      (*T)->right=k->left;      k->left=*T;      (*T)->size=node_size((*T)->left)+node_size((*T)->right)+1;      k->size=node_size(k->left)+node_size(k->right)+1;      *T=k;  }  void Insert(Treap *T,int pretty,int fix){      if(*T == NULL){          *T=&_treap[sz++];          (*T)->left=(*T)->right=NULL;          (*T)->pretty=pretty,(*T)->size=1,(*T)->fix=fix;      }else if(pretty < (*T)->pretty){          Insert(&((*T)->left),pretty,fix);          if((*T)->left->fix < (*T)->fix)              rotate_right(T);          (*T)->size=node_size((*T)->left)+node_size((*T)->right)+1;      }else if(pretty >= (*T)->pretty){          Insert(&((*T)->right),pretty,fix);          if((*T)->right->fix < (*T)->fix)              rotate_left(T);          (*T)->size=node_size((*T)->left)+node_size((*T)->right)+1;      }  }  void Remove(Treap *T,int pretty){      if(pretty == (*T)->pretty){          if((*T)->left==NULL || (*T)->right==NULL){              if((*T)->left!=NULL)                  *T=(*T)->left;              else                  *T=(*T)->right;          }else if((*T)->left->fix < (*T)->right->fix){              rotate_right(T);              (*T)->size--;              Remove(&((*T)->right),pretty);          }else if((*T)->left->fix > (*T)->right->fix){              rotate_left(T);              (*T)->size--;              Remove(&((*T)->left),pretty);          }      }else if(pretty < (*T)->pretty){          (*T)->size--;          Remove(&((*T)->left),pretty);      }else{          (*T)->size--;          Remove(&((*T)->right),pretty);      }  }  Treap find_kth(Treap T,int k){      int x = node_size(T->left);      if(k < x + 1 ) return find_kth(T->left,k);      else if(x + 1 < k) return find_kth(T->right,k-(x+1));      return T;  }  void swap(int *a,int *b){      int t=*a;      *a=*b;      *b=t;  }  int cmp(const void *a,const void *b){      node t1=*(node *)a,t2=*(node *)b;      return t1.left - t2.left;  }  int cmp_t(const void *a,const void *b){      node t1=*(node *)a,t2=*(node *)b;      return t1.id - t2.id;  }  int main()  {  #ifdef LOCAL      freopen("input.txt","r",stdin);  #endif      int i,r,l,n,m;      while(EOF!=scanf("%d %d",&n,&m)){          sz=0;          Treap T=NULL;          memset(pair,0,sizeof(pair));          for(i=1;i<=n;i++) scanf("%d",&pair[i]);          for(i=1;i<=m;i++){              scanf("%d %d %d",&rec[i].left,&rec[i].right,&rec[i].k);              if(rec[i].left > rec[i].right) swap(&rec[i].left,&rec[i].right);              rec[i].id=i;          }          qsort(&rec[1],m,sizeof(rec[0]),cmp);          l=rec[1].left,r=0;          for(i=1;i<=m;i++){              while(rec[i].left > l) if(l <= r) Remove(&T,pair[l++]);              while(rec[i].right < r) Remove(&T,pair[--r]);              if(r < l) r=l;              while(r <= rec[i].right) Insert(&T,pair[r++],Redom());              rec[i].ans=find_kth(T,rec[i].k)->pretty;          }          qsort(&rec[1],m,sizeof(rec[0]),cmp_t);          for(i=1;i<=m;i++) printf("%d\n",rec[i].ans);      }      return 0;  }