【bzoj4864】[BeiJing 2017 Wc]神秘物质 Splay

#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 200010
using namespace std;
int fa[N] , c[2][N] , si[N] , w[N] , maxn[N] , minn[N] , dl[N] , dr[N] , ms[N] , root;
char str[10];
int abs(int x)
{
	return x > 0 ? x : -x;
}
void pushup(int x)
{
	si[x] = si[c[0][x]] + si[c[1][x]] + 1;
	dl[x] = c[0][x] ? dl[c[0][x]] : x;
	dr[x] = c[1][x] ? dr[c[1][x]] : x;
	maxn[x] = max(w[x] , max(maxn[c[0][x]] , maxn[c[1][x]]));
	minn[x] = min(w[x] , min(minn[c[0][x]] , minn[c[1][x]]));
	ms[x] = min(ms[c[0][x]] , ms[c[1][x]]);
	if(c[0][x]) ms[x] = min(ms[x] , abs(w[x] - w[dr[c[0][x]]]));
	if(c[1][x]) ms[x] = min(ms[x] , abs(w[x] - w[dl[c[1][x]]]));
}
void build(int l , int r , int f)
{
	if(l > r) return;
	int mid = (l + r) >> 1;
	build(l , mid - 1 , mid) , build(mid + 1 , r , mid);
	fa[mid] = f , c[mid > f][f] = mid;
	pushup(mid);
}
void rotate(int &k , int x)
{
	int y = fa[x] , z = fa[y] , l = (c[1][y] == x) , r = l ^ 1;
	if(y == k) k = x;
	else c[c[1][z] == y][z] = x;
	fa[x] = z , fa[y] = x , fa[c[r][x]] = y , c[l][y] = c[r][x] , c[r][x] = y;
	pushup(y) , pushup(x);
}
void splay(int &k , int x)
{
	while(x != k)
	{
		int y = fa[x] , z = fa[y];
		if(y != k)
		{
			if((c[0][z] == y) ^ (c[0][y] == x)) rotate(k , x);
			else rotate(k , y);
		}
		rotate(k , x);
	}
}
int find(int k , int x)
{
	if(x <= si[c[0][k]]) return find(c[0][k] , x);
	else if(x > si[c[0][k]] + 1) return find(c[1][k] , x - si[c[0][k]] - 1);
	else return k;
}
int split(int l , int r)
{
	int a = find(root , l - 1) , b = find(root , r + 1);
	splay(root , a) , splay(c[1][root] , b);
	return c[0][c[1][root]];
}
int main()
{
	int n , m , i , x , y , t , tot;
	scanf("%d%d" , &n , &m) , tot = n + 2;
	for(i = 2 ; i <= n + 1 ; i ++ ) scanf("%d" , &w[i]);
	maxn[0] = 0 , minn[0] = ms[0] = 0x3fffffff;
	build(1 , n + 2 , 0) , root = (n + 3) >> 1;
	while(m -- )
	{
		scanf("%s%d%d" , str , &x , &y);
		switch(str[1])
		{
			case ‘e‘: t = split(x + 1 , x + 2) , c[0][t] = c[1][t] = 0 , w[t] = y , 
			          pushup(t) , pushup(c[1][root]) , pushup(root); break;
			case ‘n‘: split(x + 2 , x + 1) , c[0][c[1][root]] = ++tot , w[tot] = y , fa[tot] = c[1][root] , 
			          pushup(tot) , pushup(c[1][root]) , pushup(root); break;
			case ‘a‘: t = split(x + 1 , y + 1) , printf("%d\n" , maxn[t] - minn[t]); break;
			default: printf("%d\n" , ms[split(x + 1 , y + 1)]);
		}
	}
	return 0;
}