[树状数组] poj 2155 Matrix

题目分析

代码

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
#include<map>
using namespace std;
const int maxn=1005;
int n,q;
bool bit[maxn][maxn];
inline int lowbit(int x){return x&-x;}
void add(int x,int y)
{
for(int i=x;i<=n;i+=lowbit(i))
for(int j=y;j<=n;j+=lowbit(j)) bit[i][j]=!bit[i][j];
}
void update(int x1,int y1,int x2,int y2)
{
add(x1,y1);
add(x1,y2+1);
add(x2+1,y1);
add(x2+1,y2+1);
}
int getsum(int x,int y)
{
bool res=0;
for(int i=x;i>0;i-=lowbit(i))
for(int j=y;j>0;j-=lowbit(j)) res^=bit[i][j];
return res;
}
char op[2];
int main()
{
int T;
cin>>T;
while(T--)
{
cin>>n>>q;
int x1,y1,x2,y2;
for(int i=1;i<=n;i++) memset(bit[i],0,(n+1)*sizeof(int));
while(q--)
{
scanf("%s%d%d",op,&x1,&y1);
if(op[0]=='C')
{
scanf("%d%d",&x2,&y2);
update(x1,y1,x2,y2);
}
else cout<<getsum(x1,y1)<<endl;
}
if(T) cout<<endl;
}
return 0;
}