MATSUM - Matrix Summation
A N × N matrix is filled with numbers. BuggyD is analyzing the matrix, and he wants the sum of certain submatrices every now and then, so he wants a system where he can get his results from a query. Also, the matrix is dynamic, and the value of any cell can be changed with a command in such a system.
Assume that initially, all the cells of the matrix are filled with 0. Design such a system for BuggyD. Read the input format for further details.
The first line of the input contains an integer t, the number of test cases. t test cases follow.
The first line of each test case contains a single integer N (1 <= N <= 1024), denoting the size of the matrix.
A list of commands follows, which will be in one of the following three formats (quotes are for clarity):
- "SET x y num" - Set the value at cell (x, y) to num (0 <= x, y < N).
- "SUM x1 y1 x2 y2" - Find and print the sum of the values in the rectangle from (x1, y1) to (x2, y2), inclusive. You may assume that x1 <= x2 and y1 <= y2, and that the result will fit in a signed 32-bit integer.
- "END" - Indicates the end of the test case.
For each test case, output one line for the answer to each "SUM" command. Print a blank line after each test case.
Input: 1 4 SET 0 0 1 SUM 0 0 3 3 SET 2 2 12 SUM 2 2 2 2 SUM 2 2 3 3 SUM 0 0 2 2 END Output: 1 12 12 13
A nice 2D BIT problem, int works
Easy one if you Know 2d bit
It can be solved with 2D Segment Tree
cin/cout (optimized to avoid flushes); bit2d<int> 0.30s; bit2d<long long> 0.33s
Nice problem to learn 2D BIT
2d-Segment Tree with most optimizations => TLE
Chandan Kumar Rai:
In java , Bit2d give TLE .. any suggestions for AC
Hi guys ......if you got a Runtime error(SIGSEGV),change all the long long to int .
can any one give some test cases , I am getting error(SIGSEGV) .
NICE QUESTION TO LEARN 2D BIT