BZOJ 1500: [NOI2005] 维修数列
Input
输入的第 1 行包含两个数 N 和 M(M ≤20 000)，N 表示初始时数列中数的个数，M 表示要进行的操作数目。
第 2 行包含 N 个数字，描述初始时的数列。
以下 M 行，每行一条命令，格式参见问题描述中的表格。
任何时刻数列中最多含有 500 000 个数，数列中任何一个数字均在 [-1 000, 1 000] 内。
插入的数字总数不超过 4 000 000 个，输入文件大小不超过 20MBytes。
Output
对于输入数据中的 GET-SUM 和 MAX-SUM 操作，向输出文件依次打印结果，每个答案（数字）占一行。
Sample Input
9 8
2 -6 3 5 1 -5 -3 6 3
GET-SUM 5 4
MAX-SUM
INSERT 8 3 -5 7 2
DELETE 12 1
MAKE-SAME 3 3 2
REVERSE 3 6
GET-SUM 5 4
MAX-SUM
2 -6 3 5 1 -5 -3 6 3
GET-SUM 5 4
MAX-SUM
INSERT 8 3 -5 7 2
DELETE 12 1
MAKE-SAME 3 3 2
REVERSE 3 6
GET-SUM 5 4
MAX-SUM
Sample Output
-1
10
1
10
10
1
10
传说中巨变态的一道题。。。调了一下午终于AC了。。。模板：Orz神犇黄学长 @hzwer
血的教训：
边界值一定要初始化！边界值一定要初始化！边界值一定要初始化！重要的事情说三遍！
放代码：
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
const int MAXN = 1000005, INF = 0x3f3f3f3f;
int N, M, root, spa[MAXN], top, A[MAXN], id[MAXN], tot;
int rd(){
int x=0, f=0, ch = getchar();
while(ch<'0'||'9'<ch){if(ch=='-')f=-1;ch=getchar();};
while('0'<=ch&&ch<='9'){x=x*10+ch-'0';ch=getchar();};
return f?-x:x;
}
struct SplayTree{
int fa[MAXN], ch[MAXN][2];
int v[MAXN], sz[MAXN], sum[MAXN], lx[MAXN], rx[MAXN], mx[MAXN];
int cov[MAXN], rev[MAXN];
void trace(){
printf("root=%d, tot=%d\n", root, tot);
for(int i = 0; i <= N+2; ++i){
printf("%d: ", i);
printf("fa=%d, ch[0]=%d, ch[1]=%d, v=%d, sz=%d,\n",
fa[i], ch[i][0], ch[i][1], v[i], sz[i]);
printf("sum=%d, lx=%d, rx=%d, mx=%d, cov=%d, rev=%d;\n",
sum[i], lx[i], rx[i], mx[i], cov[i], rev[i]);
}
}
void dfs(int x){
if(x == 0) return;
dfs(ch[x][0]);
if(v[x] != -INF)printf("%d ", v[x]);
dfs(ch[x][1]);
}
void pushup(int x){
int l = ch[x][0], r = ch[x][1];
sz[x] = 1 + sz[l] + sz[r];
sum[x] = v[x] + sum[l] + sum[r];
lx[x] = max(lx[l], sum[l] + v[x] + lx[r]);
rx[x] = max(rx[r], sum[r] + v[x] + rx[l]);
mx[x] = max(rx[l] + v[x] + lx[r], max(mx[l], mx[r]));
}
void pushdown(int x){
int l = ch[x][0], r = ch[x][1];
if(cov[x] != INF){
if(l){
v[l] = cov[x];
sum[l] = sz[l] * cov[x];
lx[l] = rx[l] = cov[x] > 0 ? sum[l] : 0;
mx[l] = cov[x] > 0 ? sum[l] : cov[x];
cov[l] = cov[x]; rev[l] = 0;
}
if(r){
v[r] = cov[x];
sum[r] = sz[r] * cov[x];
lx[r] = rx[r] = cov[x] > 0 ? sum[r] : 0;
mx[r] = cov[x] > 0 ? sum[r] : cov[x];
cov[r] = cov[x]; rev[r] = 0;
}
cov[x] = INF; rev[x] = 0;
}
else if(rev[x]){
rev[l] ^= 1; rev[r] ^= 1; rev[x] = 0;
swap(lx[l], rx[l]); swap(lx[r], rx[r]);
swap(ch[l][0], ch[l][1]); swap(ch[r][0], ch[r][1]);
}
}
void rot(int x, int &k){
int y = fa[x], z = fa[y], l = ch[y][1] == x, r = l ^ 1;
if(y == k) k = x;
else ch[z][ch[z][1] == y] = x;
fa[ch[x][r]] = y; fa[y] = x; fa[x] = z;
ch[y][l] = ch[x][r]; ch[x][r] = y;
pushup(y); pushup(x);
}
void splay(int x, int &k){
while(x != k){
int y = fa[x], z = fa[y];
if(y != k){
if((ch[y][1] == x) ^ (ch[z][1] == y)) rot(x, k);
else rot(y, k);
}
rot(x, k);
}
}
int srch(int x, int k){
pushdown(x);
int l = ch[x][0], r = ch[x][1];
if(k == sz[l] + 1) return x;
if(k <= sz[l]) return srch(l, k);
return srch(r, k - sz[l] - 1);
}
int &split(int k, int t){
int x = srch(root, k), y = srch(root, k + t + 1);
splay(x, root); splay(y, ch[x][1]);
return ch[y][0];
}
void build(int &x, int f, int L, int R){
if(L > R) return;
if(L == R){
x = id[L]; fa[x] = f; v[x] = sum[x] = mx[x] = A[L];
sz[x] = 1; cov[x] = INF; rev[x] = 0;
if(A[L] > 0) lx[x] = rx[x] = A[L];
else lx[x] = rx[x] = 0;
return;
}
int mid = (L + R) >> 1;
x = id[mid]; fa[x] = f; v[x] = A[mid]; cov[x] = INF; rev[x] = 0;
build(ch[x][0], x, L, mid-1);
build(ch[x][1], x, mid+1, R);
pushup(x);
}
void ins(){
int k = rd(), t = rd(), x, y;
for(int i = 1; i <= t; ++i){
A[i] = rd();
id[i] = top ? spa[--top] : ++tot;
}
x = srch(root, k+1), y = srch(root, k+2);
splay(x, root); splay(y, ch[x][1]);
build(ch[y][0], y, 1, t);
pushup(y); pushup(x);
}
void rec(int x){
if(!x) return;
rec(ch[x][0]); rec(ch[x][1]);
fa[x] = ch[x][0] = ch[x][1] = 0;
cov[x] = INF; rev[x] = 0;
spa[top++] = x;
}
void del(){
int k = rd(), t = rd();
int &x = split(k, t), y = fa[x];
rec(x); x = 0;
pushup(y); pushup(fa[y]);
}
void modify(){
int k = rd(), t = rd(), c = rd();
int &x = split(k, t), y = fa[x];
cov[x] = v[x] = c; sum[x] = c * sz[x]; rev[x] = 0;
if(c < 0){
lx[x] = rx[x] = 0; mx[x] = c;
}else{
lx[x] = rx[x] = mx[x] = sum[x];
}
pushup(y); pushup(fa[y]);
}
void rever(){
int k = rd(), t = rd();
int x = split(k, t), y = fa[x];
rev[x] ^= 1;
swap(ch[x][0], ch[x][1]);
swap(lx[x], rx[x]);
pushup(y); pushup(fa[y]);
}
void gsum(){
int k = rd(), t = rd();
if(t == 0){printf("0\n"); return; }
int x = split(k, t);
printf("%d\n", sum[x]);
}
void gmax(){
printf("%d\n", mx[root]);
}
}spt;
char opt[128];
int main(){
freopen("sequence9.in", "r", stdin);
freopen("my.txt", "w", stdout);
scanf("%d%d", &N, &M);
for(int i = 2; i <= N + 1; ++i){
A[i] = rd(); id[i] = ++tot;
}
spt.mx[0] = A[1] = A[N+2] = -INF; id[1] = ++tot; id[N+2] = ++tot; //重要！
spt.build(root, 0, 1, N+2);
memset(spt.cov, 0x3f, sizeof(spt.cov));
for(int i = 1; i <= M; ++i){
// spt.trace();
// spt.dfs(root); putchar('\n');
scanf("%s", opt);
// printf("%d: %s %d\n", i, opt, spt.sz[root]);
switch(opt[0]){
case 'I':
spt.ins();
break;
case 'D':
spt.del();
break;
case 'R':
spt.rever();
break;
case 'G':
spt.gsum();
break;
case 'M':
if(opt[2] == 'K'){
spt.modify();
}else{
spt.gmax();
}
break;
}
}
return 0;
}
退役
