bzoj 1500 维修数列

splay插入，删除，区间翻转，区间修改，区间求和，区间最大子段和。

要把splay 的删除后的结点编号，重新利用，不然会MLE。初始化的时候，a[0] = a[n+1] = -inf;

sum[0] = 0; lsum[0] = rsum[0] = mx[0] = -inf;不然区间求子段和的时候有负数的时候就跪了（因为lsum[0], rsum[0], mx[0]默认是0)。

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

using namespace std;

#pragma comment(linxer, "/STACK:102400000,102400000")
#define LL long long
#define pii pair<int, int>
#define MP maxe_pair
#define ls i << 1
#define rs ls | 1
#define md (ll + rr >> 1)
#define lson ll, md, ls
#define rson md + 1, rr, rs
#define mod 1000000007
#define inf 0x3f3f3f3f
#define N 700020
#define M 500010

int ch
[2], pre
, sz
, a
, val
;
int sum
, lsum
, rsum
, mx
, down
;
int n, root, tot;
bool f
, ok;
queue<int> q;

void init(int x){
if(!x) return ;
q.push(x);
init(ch[x][0]);
init(ch[x][1]);
ch[x][0] = ch[x][1] = 0;
sum[x] = lsum[x] = rsum[x] = -inf;
}
int creat(int v, int fa){
int x = q.front(); q.pop();
pre[x] = fa;
ch[x][0] = ch[x][1] = 0;
val[x] = sum[x] = v;
mx[x] = lsum[x] = rsum[x] = v;
sz[x] = 1;
down[x] = inf;
f[x] = 0;
return x;
}
void push_up(int x){
int lx = ch[x][0], rx = ch[x][1];
sz[x] = sz[lx] + sz[rx] + 1;
sum[x] = sum[lx] + sum[rx] + val[x];
lsum[x] = max(lsum[lx], sum[lx] + max(0, lsum[rx]) + val[x]);
rsum[x] = max(rsum[rx], sum[rx] + max(0, rsum[lx]) + val[x]);
mx[x] = max(0, rsum[lx]) + max(0, lsum[rx]) + val[x];
mx[x] = max(mx[x], max(mx[lx], mx[rx]));
}
void push_lazy(int x, int v){
sum[x] = sz[x] * v;
val[x] = v;
mx[x] = lsum[x] = rsum[x] = max(v, sum[x]);
down[x] = v;
}
void push_down(int x){
if(f[x]){
swap(ch[x][0], ch[x][1]);
if(ch[x][0]) f[ch[x][0]] ^= 1, swap(lsum[ch[x][0]], rsum[ch[x][0]]);
if(ch[x][1]) f[ch[x][1]] ^= 1, swap(lsum[ch[x][1]], rsum[ch[x][1]]);
f[x] = 0;
}
if(down[x] != inf){
if(ch[x][0]) push_lazy(ch[x][0], down[x]);
if(ch[x][1]) push_lazy(ch[x][1], down[x]);
down[x] = inf;
}
}
int build(int ll, int rr, int fa){
if(ll > rr) return 0;
int x = creat(a[md], fa);
ch[x][0] = build(ll, md - 1, x);
ch[x][1] = build(md + 1, rr, x);
push_up(x);
return x;
}
void rotate(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(pre[x])
P(pre[x]);
push_down(x);
}
void splay(int x, int goal){
P(x);
while(pre[x] != goal){
int fa = pre[x], ff = pre[fa];
if(ff == goal)
rotate(x);
else if((ch[ff][1] == fa) == (ch[fa][1] == x))
rotate(fa), rotate(x);
else
rotate(x), rotate(x);
}
push_up(x);
if(goal == 0) root = x;
}
int Kth(int k){
int x = root;
while(x){
push_down(x);
if(sz[ch[x][0]] >= k) x = ch[x][0];
else{
k -= sz[ch[x][0]] + 1;
if(k == 0) return x;
x = ch[x][1];
}
}
return x;
}

void output(int x){
if(!x) return ;
push_down(x);
output(ch[x][0]);
if(val[x] < inf){
if(!ok) ok = 1;
else printf(" ");
printf("%d", val[x]);
}
output(ch[x][1]);
}
void Insert(int k, int cnt){
splay(Kth(k+1), 0);
splay(Kth(k+2), root);
int fa = ch[root][1];
ch[fa][0] = build(1, cnt, fa);
push_up(fa);
push_up(root);
}
void Delete(int L, int R){
splay(Kth(L), 0);
splay(Kth(R+2), root);
int fa = ch[root][1];
init(ch[fa][0]);
ch[fa][0] = 0;
push_up(fa);
push_up(root);
}
void Makesame(int L, int R, int c){
splay(Kth(L), 0);
splay(Kth(R+2), root);
int fa = ch[root][1];
push_lazy(ch[fa][0], c);
push_up(fa);
push_up(root);
}
int main(){
int n, m;
scanf("%d%d", &n, &m);
for(int i = 1; i <= 700000; ++i)
q.push(i);
for(int i = 1; i <= n; ++i)
scanf("%d", &a[i]);
a[0] = a[n+1] = -inf;
sum[0] = 0; lsum[0] = rsum[0] = mx[0] = -inf;
root = build(0, n + 1, 0);
char s[20];
int cur, cnt, c;
while(m--){
scanf("%s", s);
if(s[0] == 'I'){
scanf("%d%d", &cur, &cnt);
for(int i = 1; i <= cnt; ++i)
scanf("%d", &a[i]);
Insert(cur, cnt);
n += cnt;
//  output(root); puts("");
}
else if(s[0] == 'D'){
scanf("%d%d", &cur, &cnt);
Delete(cur, cur + cnt - 1);
n -= cnt;
//  output(root); puts("");
}
else if(s[0] == 'M' && s[2] == 'K'){
scanf("%d%d%d", &cur, &cnt, &c);
Makesame(cur, cur + cnt - 1, c);
}
else if(s[0] == 'R'){
scanf("%d%d", &cur, &cnt);
int L = cur, R = cur + cnt - 1;
splay(Kth(L), 0);
splay(Kth(R+2), root);
int fa = ch[root][1];
int x = ch[fa][0];
f[x] ^= 1;
swap(lsum[x], rsum[x]);
}
else if(s[0] == 'G'){
scanf("%d%d", &cur, &cnt);
int L = cur, R = cur + cnt - 1;
splay(Kth(L), 0);
splay(Kth(R+2), root);
int fa = ch[root][1];
printf("%d\n", sum[ch[fa][0]]);
}
else{
int L = 1, R = n;
splay(Kth(L), 0);
splay(Kth(R+2), root);
int fa = ch[root][1];
printf("%d\n", mx[ch[fa][0]]);
}
}
return 0;
}