hdu1754I Hate It(splay)

  1 #include <iostream>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<algorithm>
  5 #include<stdlib.h>
  6 #include<vector>
  7 #include<cmath>
  8 #include<queue>
  9 #include<set>
 10 using namespace std;
 11 #define N 200010
 12 #define LL __int64
 13 #define INF 0xfffffff
 14 #define key_value ch[ch[root][1]][0]
 15 const double eps = 1e-8;
 16 const double pi = acos(-1.0);
 17 const double inf = ~0u>>2;
 18 int pre[N],s[N],size[N];
 19 int ch[N][2],a[N],val[N];
 20 int root,n,tot;
 21 void newnode(int &x,int k,int fa)
 22 {
 23     x = ++tot;
 24     ch[x][0]=ch[x][1] = 0;
 25     pre[x] = fa;
 26     size[x] = 1;
 27     s[x] = k;
 28     val[x] = k;
 29 }
 30 void pushup(int w)
 31 {
 32     size[w] = size[ch[w][0]]+size[ch[w][1]]+1;
 33     s[w] = max(max(s[ch[w][0]],s[ch[w][1]]),val[w]);
 34    // cout<<s[w]<<" "<<w<<"// "<<" "<<ch[w][1]<<" "<<s[w]<<endl;
 35 }
 36 void rotate(int r,int kind)
 37 {
 38     int y = pre[r];
 39     ch[y][!kind] = ch[r][kind];
 40     pre[ch[r][kind]] = y;
 41     if(pre[y])
 42     {
 43         ch[pre[y]][ch[pre[y]][1]==y] = r;
 44     }
 45     pre[r] = pre[y];
 46     ch[r][kind] = y;
 47     pre[y] = r;
 48     pushup(y);
 49     //pushup(r);
 50 }
 51 void splay(int r,int goal)
 52 {
 53     while(pre[r]!=goal)
 54     {
 55        if(pre[pre[r]]==goal)
 56         {
 57              rotate(r,ch[pre[r]][0]==r);
 58         }
 59         else
 60         {
 61             int y = pre[r];
 62             int kind = (ch[pre[y]][0]==y);
 63             if(ch[y][kind]==r)
 64             {
 65                 rotate(r,!kind);
 66                 rotate(r,kind);
 67             }
 68             else
 69             {
 70                 rotate(y,kind);
 71                 rotate(r,kind);
 72             }
 73         }
 74     }
 75     pushup(r);
 76     if(goal==0) root = r;
 77 }
 78 int get_k(int k)
 79 {
 80     int r = root;
 81     while(size[ch[r][0]]!=k)
 82     {
 83         if(size[ch[r][0]]>k)
 84         r = ch[r][0];
 85         else
 86         {
 87             k-=(size[ch[r][0]]+1);
 88             r = ch[r][1];
 89         }
 90     }
 91     return r;
 92 }
 93 int query(int l,int r)
 94 {
 95     splay(get_k(l-1),0);
 96     splay(get_k(r+1),root);
 97     return s[key_value];
 98 }
 99 /*void update(int l,int r,int k)
100 {
101     splay(get_k(l-1),0);
102     splay(get_k(r+1),root);
103     val[key_value] = k;
104     s[key_value] = k;
105     pushup(ch[root][1]);
106     pushup(root);
107 }*/
108 void update(int l,int r,int k)
109 {
110     int kk = get_k(l);
111     val[kk] = k;
112     splay(kk,0);
113 }
114 void build(int &w,int l,int r,int fa)
115 {
116     if(l>r) return ;
117     int m = (l+r)>>1;
118     newnode(w,a[m],fa);
119     build(ch[w][0],l,m-1,w);
120     build(ch[w][1],m+1,r,w);
121     pushup(w);
122 }
123 void init()
124 {
125     int i;
126     for(i = 0 ;i < n ;i++)
127     scanf("%d",&a[i]);
128     ch[0][0] = ch[0][1] = pre[0] = size[0] = s[0] = 0;
129     root = tot =0;
130     newnode(root,-1,0);
131     newnode(ch[root][1],-1,root);
132     size[root] = 2;
133     build(key_value,0,n-1,ch[root][1]);
134     pushup(ch[root][1]);
135     pushup(root);
136 }
137 int main()
138 {
139     int q,x,y,i;
140     char sq[10];
141     while(scanf("%d%d",&n,&q)!=EOF)
142     {
143         init();
144         while(q--)
145         {
146             scanf("%s%d%d",sq,&x,&y);
147             if(sq[0]==‘U‘)
148             {
149                 update(x,x,y);
150                 /*for(i = 0; i <= n+2; i++)
151                 cout<<ch[i][0]<<" "<<ch[i][1]<<" "<<i<<endl;
152                 puts("");*/
153             }
154             else
155             {
156                 printf("%d\n",query(x,y));
157                 /*for(i = 0; i <= n+2; i++)
158                 cout<<ch[i][0]<<" "<<ch[i][1]<<" "<<i<<endl;
159                 puts("");*/
160             }
161         }
162     }
163     return 0;
164 }