1074. Number of Submatrices That Sum to Target.cpp

// ***
//
// Given a matrix and a target, return the number of non-empty submatrices that sum to target.
// 
// A submatrix x1, y1, x2, y2 is the set of all cells matrix[x][y] with x1 <= x <= x2 and y1 <= y <= y2.
// 
// Two submatrices (x1, y1, x2, y2) and (x1', y1', x2', y2') are different if they have some coordinate that is different: for example, if x1 != x1'.
// 
// 
// Example 1:
// 
// Input: matrix = [[0,1,0],[1,1,1],[0,1,0]], target = 0
// Output: 4
// Explanation: The four 1x1 submatrices that only contain 0.
// 
// 
// Example 2:
// 
// Input: matrix = [[1,-1],[-1,1]], target = 0
// Output: 5
// Explanation: The two 1x2 submatrices, plus the two 2x1 submatrices, plus the 2x2 submatrix.
// 
// 
// Example 3:
// 
// Input: matrix = [[904]], target = 0
// Output: 0
//
// ***

// TODO
class Solution {
public:
    int numSubmatrixSumTarget(vector<vector<int>>& matrix, int target) {
    }
};