POJ2155 Matrix <树套树/二维树状数组>

Problem

Matrix

Time Limit:
Memory Limit:

Description

Given an matrix , whose elements are either or . means the number in the row and column. Initially we have .
We can change the matrix in the following way. Given a rectangle whose upper-left corner is and lower-right corner is , we change all the elements in the rectangle by using “not” operation (if it is a ‘’ then change it into ‘’ otherwise change it into ‘’). To maintain the information of the matrix, you are asked to write a program to receive and execute two kinds of instructions.

() changes the matrix by using the rectangle whose upper-left corner is and lower-right corner is .
() querys .

Input

The first line of the input is an integer representing the number of test cases. The following X blocks each represents a test case.
The first line of each block contains two numbers and (, ) representing the size of the matrix and the number of the instructions. The following lines each represents an instruction having the format “ ” or “ ”, which has been described above.

Output

For each querying output one line, which has an integer representing .
There is a blank line between every two continuous test cases.

Sample Input

Sample Output

标签：线段树套线段树/二维树状数组

Solution

此题最简单的方法是二维树状数组，但因为二维树状数组没太大用，所以练习线段树的树套树。
此题用作树套树的模板题再合适不过。

Code

#include <iostream>
#include <cstdio>
#include <cstring>
#define MAX_N 1000
using namespace std;
int n, m;
int tr[(MAX_N<<2)+5][(MAX_N<<2)+5];
void modify_y(int v1, int v2, int s, int t, int l, int r) {
    if (s >= l && t <= r) {
        tr[v1][v2] ^= 1;
        return;
    }
    int mid = s+t>>1;
    if (l <= mid)	modify_y(v1, v2<<1, s, mid, l, r);
    if (r >= mid+1)	modify_y(v1, v2<<1|1, mid+1, t, l, r);
}
void modify_x(int v, int s, int t, int x1, int y1, int x2, int y2) {
    if (s >= x1 && t <= x2) {
        modify_y(v, 1, 1, n, y1, y2);
        return;
    }
    int mid = s+t>>1;
    if (x1 <= mid)	modify_x(v<<1, s, mid, x1, y1, x2, y2);
    if (x2 >= mid+1)	modify_x(v<<1|1, mid+1, t, x1, y1, x2, y2);
}
int query_y(int v1, int v2, int s, int t, int pos) {
    if (s == t)	return tr[v1][v2];
    int mid = s+t>>1;
    if (pos <= mid)	return tr[v1][v2]^query_y(v1, v2<<1, s, mid, pos);
    else	return tr[v1][v2]^query_y(v1, v2<<1|1, mid+1, t, pos);
}
int query_x(int v, int s, int t, int x, int y) {
    if (s == t)	return query_y(v, 1, 1, n, y);
    int mid = s+t>>1;
    if (x <= mid)	return query_y(v, 1, 1, n, y)^query_x(v<<1, s, mid, x, y);
    else	return query_y(v, 1, 1, n, y)^query_x(v<<1|1, mid+1, t, x, y);
}
int main() {
    int T;
    scanf("%d", &T);
    while (T--) {
        memset(tr, 0, sizeof(tr));
        scanf("%d%d", &n, &m);
        while (m--) {
            char ch;
            cin >> ch;
            if (ch == 'C') {
                int x1, y1, x2, y2;
                scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
                modify_x(1, 1, n, x1, y1, x2, y2);
            }
            if (ch == 'Q') {
                int x, y;
                scanf("%d%d", &x, &y);
                printf("%d\n", query_x(1, 1, n, x, y));
            }
        }
        printf("\n");
    }
    return 0;
}