poj 3277 线段树

  这道题搞了我好久啊。。。真的好久，心中的一个疙瘩！最后还是求助我们班的大牛，再上网看看别人写的。才弄出来。。不容易啊。不过和别人的对比之后，才发现自己的代码还是不够“美”。好好努力吧，孩子

 

#include <iostream>
#include <algorithm>
#include <fstream>

#define MAXN 40005

using namespace std;

struct seg_tre{
    long long  l,r;
    long long h;
    struct seg_tre* pLeft,* pRight;
}Tree[MAXN*3];

struct CNode{
    long long l,r;
    long long h;
}Node[MAXN];

long long nNodeCount=0;
long long x[MAXN*2];
long long nCount=0,i,n;

bool cmp(CNode a,CNode b){
  return a.h<b.h;
}
int Mid(seg_tre *pRoot){
    return (pRoot->l+pRoot->r)/2;
}

void Create(seg_tre *pRoot,long long l,long long r){
      pRoot->l=l;
      pRoot->r=r;
      pRoot->h=0;
      if(l+1>=r) return;
      nNodeCount++;
      pRoot->pLeft=Tree+nNodeCount;
      nNodeCount++;
      pRoot->pRight=Tree+nNodeCount;
      Create(pRoot->pLeft,l,Mid(pRoot));
      Create(pRoot->pRight,Mid(pRoot),r);
}

void Insert(seg_tre *pRoot,long long l,long long r,long long h){
     if(pRoot->h>=h)  return;
     if(pRoot->l==l &&pRoot->r==r){
        pRoot->h=h;
        return;
     }
      if(pRoot->h>0 && pRoot->l+1<pRoot->r){
        pRoot->pLeft->h=pRoot->pRight->h=pRoot->h;
        pRoot->h=0;
     }
     if(l>=Mid(pRoot)){
        Insert(pRoot->pRight,l,r,h);
     }
     else if(r<=Mid(pRoot)){
        Insert(pRoot->pLeft,l,r,h);
     }
     else{
        Insert(pRoot->pLeft,l,Mid(pRoot),h);
        Insert(pRoot->pRight,Mid(pRoot),r,h);
     }
}

long long find(long long value){
    long long l=0;
    long long r=nCount-1;
    while(l<r){
       long long mid=(l+r)/2;
       if(x[mid]==value) return mid;
       else if(x[mid]<value)  l=mid+1;
       else r=mid-1;
    }
    return l;
}

long long cal(seg_tre *pRoot){
     if(pRoot->h>0)
         return (long long)pRoot->h*(x[pRoot->r]-x[pRoot->l]);
     if(pRoot->l+1>=pRoot->r) return 0;
     else return cal(pRoot->pLeft)+cal(pRoot->pRight);
}

int main(){

    freopen("acm.in","r",stdin);
    scanf("%lld",&n);
    for(i=0 ;i<n ;i++){
       scanf("%lld%lld%lld",&Node[i].l,&Node[i].r,&Node[i].h);
       x[nCount++]=Node[i].l;
       x[nCount++]=Node[i].r;
    }
    sort(x,x+nCount);
    nCount=unique(x,x+nCount)-x;
    sort(Node,Node+n,cmp);
    Create(Tree,0,nCount-1);
    for(i=0 ;i<n ;i++){
         Insert(Tree,find(Node[i].l),find(Node[i].r),Node[i].h);
    }
    printf("%lld\n",cal(Tree));

    return 0;
}

 下面时别人的代码。很好！我的数据结构有个就是多余的。像人家那么简洁，多好

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace  std;
__int64 i,j,k,N,min,max;
__int64 sum;
__int64 num[1000000];
typedef  struct{
  __int64 l,r;
  __int64 high;
} ac;
ac ln[1000000],old[80000];
bool cmp(__int64  a,__int64  b){
   return a<b;
}
bool cmp1(ac a,ac  b)
{
  return a.high<b.high;
}
void build(__int64 s,__int64 t,__int64 step)
{
  __int64 mid;
  mid=(s+t)/2;
  ln[step].l=s;
  ln[step].r=t;
  ln[step].high=0;
   if(1+s<t)
{
    build(s,mid,2*step);
    build(mid,t,2*step+1);
 }
}
void insert(__int64 s,__int64 t,__int64 step,__int64 hi)
{
    if(s==ln[step].l&&t==ln[step].r)
     {
       // if(hi>ln[step].high)
          ln[step].high=hi;
          return ;
    }
    else
    {
     if(ln[step].high>0)
     {
       ln[2*step].high=ln[step].high;
       ln[2*step+1].high=ln[step].high;
       ln[step].high=-1;
     }
    }
     __int64 mid=(ln[step].r+ln[step].l)/2;
     if(mid>=t)
     insert(s,t,step*2,hi);
     else
     if(s>=mid)
     insert(s,t,step*2+1,hi);
     else
     {
         insert(s,mid,2*step,hi);
         insert(mid,t,step*2+1,hi);
     }
}
void visit(__int64 step)
{
   if(ln[step].high>0)
    {
     sum=sum+ln[step].high*(num[ln[step].r]-num[ln[step].l]);
      return ;
    }
    if(ln[step].l+2>ln[step].r)     return;
    visit(2*step);
    visit(2*step+1);
}
__int64 binarysearch(__int64 value)
{
    __int64  low,hig,mid;
    low=0;
    hig=k-1;
    while(low<=hig)
    {
        mid=(low+hig)/2;
        if(num[mid]==value)
          return mid;
        else
         if(num[mid]<value)
           low=mid+1;
         else
           hig=mid-1;
    }
    return 0;
}
int main(){
   // while(1){
  scanf("%I64d",&N);
  k=0;
  for(i=0;i<N;i++)
  {
      scanf("%I64d %I64d %I64d",&old[i].l,&old[i].r,&old[i].high);
      num[k++]=old[i].l;
      num[k++]=old[i].r;
  }
  sort(num,num+k);
  k=1;
  for(i=1;i<2*N;i++)
     if(num[i]!=num[i-1])
     num[k++]=num[i];
     build(0,k-1,1);
    sort(old,old+N,cmp1);
  for(i=0;i<N;i++)
  {
    insert(binarysearch(old[i].l),binarysearch(old[i].r),1,old[i].high);
  }
  sum=0;
    visit(1);
   printf("%I64d\n",sum);
   return 0;
}