poj2155二维线段树,二维树状数组

Matrix
 
  

Time Limit: 3000MS   Memory Limit: 65536K
Total Submissions: 23048   Accepted: 8560

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]. 

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

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

一道二维线段树的题,写了好久,题目大意是给一个N*N大小的矩阵,初始赋值为0,根据要求翻转给定矩阵中的数,最后查询,一道区间修改,单点查询的题,树套树就可以了。

#include 
#include 
#include 
#define mem(a,b) memset((a),(b),sizeof(a))
#define middle int mid=(l+r)/2
#define lsonx l,mid,x*2
#define rsonx mid+1,r,x*2+1
#define lsony l,mid,y*2
#define rsony mid+1,r,y*2+1
using namespace std;
const int M=1005;
int n;
struct treey
{
    int l,r,c;
};
struct treex
{
    struct treey ntr[M<<2];
    int l,r;
} tr[M<<2];
void buildy(int l,int r,int y,int x)
{
    tr[x].ntr[y].l=l;
    tr[x].ntr[y].r=r;
    tr[x].ntr[y].c=0;
    if(l==r) return;
    middle;
    buildy(lsony,x);
    buildy(rsony,x);
}
void buildx(int l,int r,int x)
{
    tr[x].l=l;
    tr[x].r=r;
    buildy(1,n,1,x);
    if(l==r) return;
    middle;
    buildx(lsonx);
    buildx(rsonx);
}
void updatey(int x1,int y1,int x2,int y2,int x,int y)
{
    if(tr[x].ntr[y].l==y1&&tr[x].ntr[y].r==y2)
    {
        tr[x].ntr[y].c=!tr[x].ntr[y].c;
        return;
    }
    int mid=(tr[x].ntr[y].l+tr[x].ntr[y].r)/2;
    if(y2<=mid)
    {
        updatey(x1,y1,x2,y2,x,y*2);
    }
    else if(y1>mid)
    {
        updatey(x1,y1,x2,y2,x,y*2+1);
    }
    else
    {
        updatey(x1,y1,x2,mid,x,y*2);
        updatey(x1,mid+1,x2,y2,x,y*2+1);
    }
}
void updatex(int x1,int y1,int x2,int y2,int x)
{
    if(tr[x].l==x1&&tr[x].r==x2)
    {
        updatey(x1,y1,x2,y2,x,1);
        return;
    }
    int mid=(tr[x].l+tr[x].r)/2;
    if(x2<=mid)
        updatex(x1,y1,x2,y2,x*2);
    else if(x1>mid)
        updatex(x1,y1,x2,y2,x*2+1);
    else
    {
        updatex(x1,y1,mid,y2,x*2);
        updatex(mid+1,y1,x2,y2,x*2+1);
    }
}
int ans;
void get_ansy(int i,int x,int y)
{
    ans^=tr[x].ntr[y].c;
    if(tr[x].ntr[y].l==tr[x].ntr[y].r)
        return;
    int mid=(tr[x].ntr[y].l+tr[x].ntr[y].r)/2;
    if(i<=mid)
        get_ansy(i,x,y*2);
    else
        get_ansy(i,x,y*2+1);
}
void get_ansx(int x,int y,int i)
{
    get_ansy(y,i,1);
    if(tr[i].l==tr[i].r)
        return ;
    int mid=(tr[i].l+tr[i].r)/2;
    if(x<=mid)
        get_ansx(x,y,i*2);
    else
        get_ansx(x,y,i*2+1);
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int t;
        scanf("%d%d",&n,&t);
        buildx(1,n,1);
        while(t--)
        {
            char str[5];
            scanf("%s",str);
            if(str[0]=='C')
            {
                int x1,y1,x2,y2;
                scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
                updatex(x1,y1,x2,y2,1);
            }
            else if(str[0]=='Q')
            {
                int x,y;
                ans=0;
                scanf("%d%d",&x,&y);
                get_ansx(x,y,1);
                printf("%d\n",ans);
            }
        }
        printf("\n");
    }
    return 0;
}
这道题的另外一种办法,就是树状数组,这里用给定坐标与最大边界间的矩阵,因为要求翻转,所以只需要求翻转次数就可以了。奇数就是翻成了1,偶数还是0,之所以不用最小边界,是因为容易产生给定坐标值为0 0的情况。导致超出数组下届,代码如下。
#include 
#include 
#include 
#include 
#define mem(a,b) memset((a),(b),sizeof(a))
using namespace std;
const int M=1005;
int tr[M][M];
int n;
int lowbit(int x)
{
    return x&(-x);
}
void update(int x,int y)
{
    for(int i=x; i<=n; i+=lowbit(i))
        for(int j=y; j<=n; j+=lowbit(j))
        {
            tr[i][j]++;
        }
    return ;
}
int get_ans(int x,int y)
{
    int ans=0;
    for(int i=x; i>0; i-=lowbit(i))
        for(int j=y; j>0; j-=lowbit(j))
        {
            ans+=tr[i][j];
        }
    return ans;
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int t;
        scanf("%d%d",&n,&t);
        mem(tr,0);
        while(t--)
        {
            char str[5];
            scanf("%s",str);
            if(str[0]=='C')
            {
                int x1,y1,x2,y2;
                scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
                update(x2+1,y2+1);
                update(x1,y2+1);
                update(x2+1,y1);
                update(x1,y1);
            }
            else if(str[0]=='Q')
            {
                int x,y;
                scanf("%d%d",&x,&y);
                printf("%d\n",get_ans(x,y)%2);
            }
        }
        printf("\n");
    }
    return 0;
}

 
 

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