time limit per test2 seconds
memory limit per test512 megabytes
inputstandard input
outputstandard output
Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and access to it when it is modified.
After reaching home Alina decided to invent her own persistent data structure. Inventing didn’t take long: there is a bookcase right behind her bed. Alina thinks that the bookcase is a good choice for a persistent data structure. Initially the bookcase is empty, thus there is no book at any position at any shelf.
The bookcase consists of n shelves, and each shelf has exactly m positions for books at it. Alina enumerates shelves by integers from 1 to n and positions at shelves — from 1 to m. Initially the bookcase is empty, thus there is no book at any position at any shelf in it.
Alina wrote down q operations, which will be consecutively applied to the bookcase. Each of the operations has one of four types:
1 i j — Place a book at position j at shelf i if there is no book at it.
2 i j — Remove the book from position j at shelf i if there is a book at it.
3 i — Invert book placing at shelf i. This means that from every position at shelf i which has a book at it, the book should be removed, and at every position at shelf i which has not book at it, a book should be placed.
4 k — Return the books in the bookcase in a state they were after applying k-th operation. In particular, k = 0 means that the bookcase should be in initial state, thus every book in the bookcase should be removed from its position.
After applying each of operation Alina is interested in the number of books in the bookcase. Alina got ‘A’ in the school and had no problem finding this values. Will you do so?
Input
The first line of the input contains three integers n, m and q (1 ≤ n, m ≤ 103, 1 ≤ q ≤ 105) — the bookcase dimensions and the number of operations respectively.
The next q lines describes operations in chronological order — i-th of them describes i-th operation in one of the four formats described in the statement.
It is guaranteed that shelf indices and position indices are correct, and in each of fourth-type operation the number k corresponds to some operation before it or equals to 0.
Output
For each operation, print the number of books in the bookcase after applying it in a separate line. The answers should be printed in chronological order.
Examples
input
2 3 3
1 1 1
3 2
4 0
output
1
4
0
input
4 2 6
3 2
2 2 2
3 3
3 2
2 2 2
3 2
output
2
1
3
3
2
4
input
2 2 2
3 2
2 2 1
output
2
1
Note
This image illustrates the second sample case.
【题解】
要用一个数据结构要求支持以下操作
1 i j 如果i,j没有书，则在这个位置放一本书
2 i j 如果i,j有书，把这本书给去掉
3 i 把第i行,有书的地方的书去掉，原来没书的地方放上书
4 i 把书柜的状态转换到第i次操作之后;
把一个一个询问看成是树的节点。
相当于从根节点开始进行dfs一直走到树的最低端。
然后往回再回溯。再找找其他的路径。
每次节点的答案往下传。然后在新的节点开始进行操作。再往下传。
一个节点有多个儿子节点也同理;
如果不是4号操作则前面一个询问和这个询问所代表的节点连起来;
这些修改操作和异或的操作都可以用bitset实现.
#include <cstdio>
#include <iostream>
#include <bitset>
#include <vector>
using namespace std;
const int MAXN = 1200;
const int MAXQ = 1e5 + 100;
int n, m, q, opt[MAXQ] = { 0 }, key[MAXQ][2] = { 0 };
int ans[MAXQ];
bitset <MAXN> book[MAXN] = { 0 };
bitset <MAXN> temp;
vector <int> a[MAXQ];
void input(int &r)
{
r = 0;
char t = getchar();
while (!isdigit(t)) t = getchar();
while (isdigit(t)) r = r * 10 + t - '0', t = getchar();
}
void dfs(int x)
{
int x1 = key[x][0], y1 = key[x][1],len = a[x].size();
if (x == 0)
{
for (int i = 0; i <= len - 1; i++)
{
ans[a[x][i]] = ans[x];//答案往下传
dfs(a[x][i]);
}
}
if (opt[x] == 1)
{
bool changed = false;
if (!book[x1][y1])//如果原来没书
{
changed = true;
book[x1][y1] = true;
ans[x]++;
}
for (int i = 0; i <= len - 1; i++)
{
ans[a[x][i]] = ans[x];//答案往下传
dfs(a[x][i]);
}
if (changed)
book[x1][y1] = false;
}
if (opt[x] == 2)
{
bool changed = false;
if (book[x1][y1])//如果原来有书
{
changed = true;
book[x1][y1] = false;
ans[x]--;
}
for (int i = 0; i <= len - 1; i++)
{
ans[a[x][i]] = ans[x];
dfs(a[x][i]);
}
if (changed)//回溯
book[x1][y1] = true;
}
if (opt[x] == 3)//相当于异或操作
{
ans[x] -= book[key[x][0]].count();
book[key[x][0]] ^= temp;
ans[x] += book[key[x][0]].count();
for (int i = 0; i <= len - 1; i++)
{
ans[a[x][i]] = ans[x];
dfs(a[x][i]);
}
book[key[x][0]] ^= temp;//一定要进行回溯操作
}
if (opt[x] == 4)
{
for (int i = 0; i <= len - 1; i++)
{
ans[a[x][i]] = ans[x];
dfs(a[x][i]);
}
}
}
int main()
{
//freopen("F:\rush.txt", "r", stdin);
input(n); input(m); input(q);
for (int i = 1; i <= m; i++)
temp[i] = 1;
for (int i = 1; i <= q; i++)
{
input(opt[i]);
if (opt[i] == 1)
input(key[i][0]), input(key[i][1]);
if (opt[i] == 2)
input(key[i][0]), input(key[i][1]);
if (opt[i] == 3)
input(key[i][0]);
if (opt[i] == 4)
{
input(key[i][0]);
a[key[i][0]].push_back(i);
}
else
a[i - 1].push_back(i);//如果操作是1或2或3就把当前这个操作接到前一个操作后面
}
ans[0] = 0;
dfs(0);
for (int i = 1; i <= q; i++)
printf("%d
", ans[i]);
return 0;
}