poj 3468 A Simple Problem with Integers(伸展树)

题意：给n个数，有两种操作，一种是查询区间和，另一种是在区间上每一个数加上v。

思路：本来线段树是非常好写的，但是为了学习伸展树练练手，就写了个伸展树。第一次写，代码基本上是抄的cxlove的Orz……http://blog.csdn.net/acm_cxlove/article/details/7815019

代码：

#include<iostream>#include<cstdio>#include<cstring>#include<string>#include<algorithm>#include<map>#include<queue>#include<set>#include<stack>#include<cmath>#include<vector>#define inf 0x3f3f3f3f#define Inf 0x3FFFFFFFFFFFFFFFLL#define eps 1e-9#define pi acos(-1.0)using namespace std;typedef long long ll;const int maxn=100000+10;int pre[maxn],ch[maxn][2],val[maxn],root,tot;int size[maxn],add[maxn],num[maxn];ll sum[maxn];int n,q;void Newnode(int & rt,int fa,int v){    rt=++tot;    pre[rt]=fa;    val[rt]=v;    sum[rt]=v;    add[rt]=0;    size[rt]=1;    ch[rt][0]=ch[rt][1]=0;}void PushUp(int rt){    size[rt]=size[ch[rt][0]]+size[ch[rt][1]]+1;    sum[rt]=sum[ch[rt][0]]+sum[ch[rt][1]]+val[rt];}void PushDown(int rt){    if(add[rt])    {        val[rt]+=add[rt];        add[ch[rt][0]]+=add[rt];        add[ch[rt][1]]+=add[rt];        sum[ch[rt][0]]+=(ll)add[rt]*size[ch[rt][0]];        sum[ch[rt][1]]+=(ll)add[rt]*size[ch[rt][1]];        add[rt]=0;    }}void Rotate(int x,int kind){    int y=pre[x];    PushDown(x);PushDown(y);    ch[y][kind^1]=ch[x][kind];    pre[ch[x][kind]]=y;    if(pre[y])        ch[pre[y]][ch[pre[y]][1]==y]=x;    pre[x]=pre[y];    ch[x][kind]=y;    pre[y]=x;    PushUp(y);}void Splay(int rt,int goal){    PushDown(rt);    while(pre[rt]!=goal)    {        if(pre[pre[rt]]==goal)            Rotate(rt,ch[pre[rt]][0]==rt);        else        {            int y=pre[rt];            int kind=ch[pre[y]][0]==y;            if(ch[y][kind]==rt)            {                Rotate(rt,kind^1);                Rotate(rt,kind);            }            else            {                Rotate(y,kind);                Rotate(rt,kind);            }        }    }    PushUp(rt);    if(goal==0) root=rt;}void RotateTo(int k,int goal){    int rt=root;    PushDown(rt);    while(size[ch[rt][0]]!=k)    {        if(size[ch[rt][0]]>k)            rt=ch[rt][0];        else        {            k-=(size[ch[rt][0]]+1);            rt=ch[rt][1];        }        PushDown(rt);    }    Splay(rt,goal);}ll Query(int l,int r){    RotateTo(l-1,0);    RotateTo(r+1,root);    return sum[ch[ch[root][1]][0]];}void Update(int l,int r,int v){    RotateTo(l-1,0);    RotateTo(r+1,root);    int tmp=ch[ch[root][1]][0];    add[tmp]+=v;    sum[tmp]+=(ll)size[tmp]*v;}void build(int l,int r,int & rt,int fa){    if(l>r) return ;    int m=(l+r)>>1;    Newnode(rt,fa,num[m]);    build(l,m-1,ch[rt][0],rt);    build(m+1,r,ch[rt][1],rt);    PushUp(rt);}void Init(){    for(int i=0;i<n;++i)        scanf("%d",&num[i]);    pre[0]=ch[0][0]=ch[0][1]=size[0]=0;    sum[0]=add[0]=0;    root=tot=0;    Newnode(root,0,-1);    Newnode(ch[root][1],root,-1);    size[root]=2;    build(0,n-1,ch[ch[root][1]][0],ch[root][1]);    PushUp(ch[root][1]);    PushUp(root);}int main(){    //freopen("in.txt","r",stdin);    //freopen("out.txt","w",stdout);    int l,r,v;    char str[5];    scanf("%d%d",&n,&q);    Init();    while(q--)    {        scanf("%s",str);        scanf("%d%d",&l,&r);        if(str[0]=='Q')            printf("%lld\n",Query(l,r));        else        {            scanf("%d",&v);            Update(l,r,v);        }    }    return 0;}