I hate it stretch tree

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# Include <stdio. h>
# Include <string. h>
# Include <algorithm>
# Include <stdlib. h>
# Include <math. h>
# Include <algorithm>
# Include <time. h>

Using namespace STD;

Int left [200100], right [200100], maxn [200100], PF [200100], value [200100], root; // a point with a value of-1 indicates that the node is empty.

Void Update (int n)
{
If (n =-1)
Return;
Else if (left [N]! =-1 & right [N]! =-1)
Maxn [N] = max (maxn [left [N], maxn [right [N]), value [N]);
Else if (left [N]! =-1)
Maxn [N] = max (maxn [left [N], value [N]);
Else if (right [N]! =-1)
Maxn [N] = max (maxn [right [N], value [N]);
Else
Maxn [N] = value [N];
}
// Right-handed
Inline void Zig (int n)
{
Int M = pf [N];
Left [m] = right [N];
PF [right [N] = m;
Right [N] = m;
If (left [pf [m] = m)
Left [pf [m] = N;
Else
Right [pf [m] = N;
Update (m );
Update (N );
PF [N] = pf [m];
PF [m] = N;
}

// Left-handed
Inline void zag (int n)
{
Int M = pf [N];
Right [m] = left [N];
PF [left [N] = m;
Left [N] = m;
If (left [pf [m] = m)
Left [pf [m] = N;
Else
Right [pf [m] = N;
Update (m );
Update (N );
PF [N] = pf [m];
PF [m] = N;

}



Inline int splay (int n, int P)
{
While (PF [N]! = P)
{
If (PF [pf [N] = P)
{
If (n = left [pf [N])
Zig (N );
Else
Zag (N );

}
Else
{
If (left [pf [pf [N] = pf [N])
{
If (left [pf [N] = N)
{
Zig (PF [N]);
Zig (N );
}
Else
{
Zag (N );
Zig (N );
}
}
Else if (right [pf [pf [N] = pf [N])
{
If (right [pf [N] = N)
{
Zag (PF [N]);
Zag (N );
}
Else
{
Zig (N );
Zag (N );
}
}
}
}
Return N;

}


Inline void insert (INT head, int N, int F, int flag) // header node number, inserted node number, and its ancestor
{
If (Head =-1)
{
If (flag = 0)
Root = N;
Else if (flag = 1)
Left [f] = N;
Else if (flag = 2)
Right [f] = N;
PF [N] = F;
Right [N] =-1;
Left [N] =-1;
Maxn [N] = value [N];
}
Else
{
If (head> N)
{
If (left [head] =-1)
Flag = 1;
Insert (left [head], n, Head, flag );
}
Else
{
If (left [head] =-1)
Flag = 2;
Insert (right [head], n, Head, flag );
}
}
Update (head );
}


Void preordertravel (int n)
{
If (n! =-1 ){
Printf ("% d's Father's Day is % d \ n", N, PF [N]);
Preordertravel (left [N]);
Preordertravel (right [N]);
}
}

Int modify (int p, int A, int B)
{
P = splay (A,-1 );
Value [a] = B;
Update ();
Return P;
}
Int main ()
{
Int n, m, A, B;
Char STR [100];
While (scanf ("% d", & N, & M )! = EOF)
{
Root =-1;
Insert (root, 0,-1, 0 );
Insert (root, n + 1,-1, 0 );
Value [0] = value [n + 1] = 0;
For (INT I = 1; I <= N; I ++)
{
Scanf ("% d", & value [I]);
Insert (root, I,-1, 0 );
Root = splay (I,-1 );
}
// Preordertravel (Root );
For (INT I = 1; I <= m; I ++)
{
Scanf ("% S % d", STR, & A, & B );
If (STR [0] = 'U ')
{
Modify (root, a, B );
Continue;
}
Root = splay (A-1,-1 );
Right [root] = splay (B + 1, root );
Printf ("% d \ n", maxn [left [right [root]);
}
}
Return 0;
}
/*
10
10
43 12 54 76 432
298 12894 1 34 5
The Father's Day in December 10 is-1.
9's Father's Day is 10
8's Father's Day is 9
7's Father's Day is 8
Father's Day is 7
Father's Day is 6
4's Father's Day is 5
3's Father's Day is 4
2's Father's Day is 3
1's Father's Day is 2
0's Father's Day is 1
11's Father's Day is 10
*/

Use the splay tree to maintain the range information and solve the range correlation quantity.

To solve the range [a, B] information, you can extend the A-1 to the root node, B + 1 to the right child of the root node.