Matrix

题解：

算法合集之《浅谈信息学竞赛中的“0”和“1”》

点击打开链接http://blog.csdn.net/zxy_snow/article/details/6264135

树状数组：

点击打开链接https://baike.baidu.com/item/%E4%BA%8C%E7%BB%B4%E6%A0%91%E7%8A%B6%E6%95%B0%E7%BB%84/20415329?fr=aladdin

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]. 

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. 

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. 

Sample Input

12 10C 2 1 2 2Q 2 2C 2 1 2 1Q 1 1C 1 1 2 1C 1 2 1 2C 1 1 2 2Q 1 1C 1 1 2 1Q 2 1

Sample Output

1001

#include<stdio.h>#include<string.h>#include<math.h>#define lowbit(x) ((x)&(-x))#define maxn 1005int c[maxn][maxn],n;void update(int x,int y){for(int i=x;i<=n;i+=lowbit(i))for(int j=y;j<=n;j+=lowbit(j))c[i][j]++;}int getSum(int x,int y){int sum=0;for(int i=x;i>0;i-=lowbit(i))for(int j=y;j>0;j-=lowbit(j))sum+=c[i][j];return sum; }int main(){int x;scanf("%d",&x);while(x--){int t;memset(c,0,sizeof(c));scanf("%d%d",&n,&t);while(t--){char ch;getchar();scanf("%c",&ch);if(ch=='Q'){int x,y;scanf("%d%d",&x,&y);printf("%d\n",getSum(x,y)&1);}else if(ch=='C'){int x1,y1,x2,y2;scanf("%d%d%d%d",&x1,&y1,&x2,&y2);x1++,y1++,x2++,y2++;update(x1-1,y2);update(x2,y1-1);update(x1-1,y1-1);update(x2,y2);}}if(x>0)printf("\n");}return 0;}