poj 3468 A Simple Problem with Integers

splay区间求和，给区间加上某个数

//#include <bits/stdc++.h>
#include <algorithm>
#include <cstdio>
#include <iostream>
#include <cstring>
#include <cmath>

using namespace std;

#define LL long long
#define inf 0x3f3f3f3f
#define MP make_pair
#define pii pair<int, int>
#define md (ll + rr >> 1)
#define N 100010
#define M 200020

int pre
, ch
[2], sz
;
int tot, root, rt
, a
;
LL sum
, add
, key
;

int creat(int p, int val){
int k = ++tot;
pre[k] = p;
ch[k][0] = ch[k][1] = 0;
sum[k] = key[k] = val;
add[k] = 0;
sz[k] = 1;
return k;
}
void push_up(int k){
sum[k] = sum[ch[k][0]] + sum[ch[k][1]] + key[k];
sz[k] = sz[ch[k][0]] + sz[ch[k][1]] + 1;
}
void _add(int k, LL val){
if(!k) return ;
key[k] += val;
sum[k] += val * sz[k];
add[k] += val;
}
void push_down(int k){
if(!k) return ;
if(add[k]){
_add(ch[k][0], add[k]);
_add(ch[k][1], add[k]);
add[k] = 0;
}
}
void rot(int x){
int y = pre[x], d = ch[y][1] == x;
ch[y][d] = ch[x][!d];
if(ch[x][!d]) pre[ch[x][!d]] = y;
ch[x][!d] = y;
pre[x] = pre[y];
pre[y] = x;
if(pre[x]) ch[pre[x]][ch[pre[x]][1] == y] = x;
push_up(y);
}
void P(int x){
if(!x) return;
P(pre[x]);
push_down(x);
}
void splay(int x, int goal){
P(x);
while(pre[x] != goal){
int f = pre[x], ff = pre[f];
if(ff == goal)
rot(x);
else if((ch[ff][1] == f) == (ch[f][1] == x))
rot(f), rot(x);
else rot(x), rot(x);
}
push_up(x);
if(goal == 0) root = x;
}
int build(int ll, int rr, int p){
if(ll > rr) return 0;
int x = creat(p, a[md]);
rt[md] = x;
ch[x][0] = build(ll, md - 1, x);
ch[x][1] = build(md + 1, rr, x);
push_up(x);
return x;
}

int main(){
int n, m;
while(scanf("%d%d", &n, &m) != EOF){
tot = 0;
for(int i = 1; i <= n; ++i)
scanf("%d", &a[i]);
a[0] = a[n + 1] = 0;
root = build(0, n + 1, 0);
while(m--){
char s[5];
int l, r, c;
scanf("%s%d%d", s, &l, &r);
if(s[0] == 'Q'){
splay(rt[l-1], 0);
splay(rt[r+1], root);
int x = ch[ch[root][1]][0];
printf("%lld\n", sum[x]);
}
else{
scanf("%d", &c);
splay(rt[l-1], 0);
splay(rt[r+1], root);
int x = ch[ch[root][1]][0];
_add(x, c);
}
}
}
return 0;
}