Package g0301_0400.s0304_range_sum_query_2d_immutable

Class NumMatrix

  • All Implemented Interfaces:
    
public final class NumMatrix

    304 - Range Sum Query 2D - Immutable\.

    Medium

    Given a 2D matrix matrix, handle multiple queries of the following type:

    • Calculate the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2).

    Implement the NumMatrix class:

    • NumMatrix(int[][] matrix) Initializes the object with the integer matrix matrix.

    • int sumRegion(int row1, int col1, int row2, int col2) Returns the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2).

    Example 1:

    Input

    ["NumMatrix", "sumRegion", "sumRegion", "sumRegion"]
[[[[3, 0, 1, 4, 2], [5, 6, 3, 2, 1], [1, 2, 0, 1, 5], [4, 1, 0, 1, 7], [1, 0, 3, 0, 5]]], [2, 1, 4, 3], [1, 1, 2, 2], [1, 2, 2, 4]]

    Output: null, 8, 11, 12

    Explanation:

    NumMatrix numMatrix = new NumMatrix([[3, 0, 1, 4, 2], [5, 6, 3, 2, 1], [1, 2, 0, 1, 5], [4, 1, 0, 1, 7], [1, 0, 3, 0, 5]]);
numMatrix.sumRegion(2, 1, 4, 3); // return 8 (i.e sum of the red rectangle)
numMatrix.sumRegion(1, 1, 2, 2); // return 11 (i.e sum of the green rectangle)
numMatrix.sumRegion(1, 2, 2, 4); // return 12 (i.e sum of the blue rectangle)

    Constraints:

    • m == matrix.length

    • n == matrix[i].length

    • 1 <= m, n <= 200

    • <code>-10<sup>5</sup><= matrixj<= 10<sup>5</sup></code>

    • 0 &lt;= row1 &lt;= row2 &lt; m

    • 0 &lt;= col1 &lt;= col2 &lt; n

    • At most <code>10<sup>4</sup></code> calls will be made to sumRegion.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description