poj-2155 Matrix(二维树状数组)
题目链接:
Matrix
Time Limit: 3000MS | Memory Limit: 65536K | |
Total Submissions: 23170 | Accepted: 8613 |
Description
Given an N*N matrix A, whose elements are either 0 or 1. A[i, j] means the number in the i-th row and j-th column. Initially we have A[i, j] = 0 (1 <= i, j <= N).
We can change the matrix in the following way. Given a rectangle whose upper-left corner is (x1, y1) and lower-right corner is (x2, y2), we change all the elements in the rectangle by using "not" operation (if it is a '0' then change it into '1' otherwise change it into '0'). To maintain the information of the matrix, you are asked to write a program to receive and execute two kinds of instructions.
1. C x1 y1 x2 y2 (1 <= x1 <= x2 <= n, 1 <= y1 <= y2 <= n) changes the matrix by using the rectangle whose upper-left corner is (x1, y1) and lower-right corner is (x2, y2).
2. Q x y (1 <= x, y <= n) querys A[x, y].
We can change the matrix in the following way. Given a rectangle whose upper-left corner is (x1, y1) and lower-right corner is (x2, y2), we change all the elements in the rectangle by using "not" operation (if it is a '0' then change it into '1' otherwise change it into '0'). To maintain the information of the matrix, you are asked to write a program to receive and execute two kinds of instructions.
1. C x1 y1 x2 y2 (1 <= x1 <= x2 <= n, 1 <= y1 <= y2 <= n) changes the matrix by using the rectangle whose upper-left corner is (x1, y1) and lower-right corner is (x2, y2).
2. Q x y (1 <= x, y <= n) querys A[x, y].
Input
The first line of the input is an integer X (X <= 10) representing the number of test cases. The following X blocks each represents a test case.
The first line of each block contains two numbers N and T (2 <= N <= 1000, 1 <= T <= 50000) representing the size of the matrix and the number of the instructions. The following T lines each represents an instruction having the format "Q x y" or "C x1 y1 x2 y2", which has been described above.
The first line of each block contains two numbers N and T (2 <= N <= 1000, 1 <= T <= 50000) representing the size of the matrix and the number of the instructions. The following T lines each represents an instruction having the format "Q x y" or "C x1 y1 x2 y2", which has been described above.
Output
For each querying output one line, which has an integer representing A[x, y].
There is a blank line between every two continuous test cases.
There is a blank line between every two continuous test cases.
Sample Input
1 2 10 C 2 1 2 2 Q 2 2 C 2 1 2 1 Q 1 1 C 1 1 2 1 C 1 2 1 2 C 1 1 2 2 Q 1 1 C 1 1 2 1 Q 2 1
Sample Output
1 0 0 1
AC代码:
#include <iostream> #include <cstdio> #include <cstring> #include <algorithm> using namespace std; const int N=1e3+4; int sum[N][N],n,l,r,xl,xr,yl,yr,m; char c; int lowbit(int x) { return x&(-x); } void update(int x,int y,int num) { while(y<=n) { int fx=x; while(fx<=n) { sum[fx][y]+=num; fx+=lowbit(fx); } y+=lowbit(y); } } int query(int x,int y) { int s=0; while(y>0){ int fx=x; while(fx>0) { s+=sum[fx][y]; fx-=lowbit(fx); } y-=lowbit(y); } return s; } int main() { int t; scanf("%d",&t); while(t--) { memset(sum,0,sizeof(sum)); scanf("%d%d",&n,&m); for(int i=0;i<m;i++) { cin>>c; if(c=='C') { scanf("%d%d%d%d",&xl,&yl,&xr,&yr); update(xl,yl,1); update(xl,yr+1,1); update(xr+1,yl,1); update(xr+1,yr+1,1); } else { scanf("%d%d",&l,&r); printf("%d\n",query(l,r)%2); } } printf("\n"); } return 0; }