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tags: leetcode
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# [2128. Remove All Ones With Row and Column Flips](https://leetcode.com/problems/remove-all-ones-with-row-and-column-flips/)
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# My Solution
## The Key Idea for Solving This Coding Question
## C++ Code

class Solution {
public:
    bool removeOnes(vector<vector<int>> &grid) {
        int rows = grid.size(), cols = grid[0].size();

        // Scan each column.
        // If the first element in a column is 1, 
        // flip all the elements in that column.
        // Otherwise, do nothing.
        for (int c = 0; c < cols; ++c) {
            if (grid[0][c] == 1) {
                for (int r = 0; r < rows; ++r) {
                    grid[r][c] ^= 1;
                }
            }
        }

        // Scan each row and count the numbers of 1.
        // If the number of ones is not zero and not equal to cols,
        // return false;
        for (int r = 0; r < rows; ++r) {
            int ones = 0;
            for (int c = 0; c < cols; ++c) {
                if (grid[r][c] == 1) {
                    ++ones;
                }
            }

            if (ones != 0 && ones != cols) {
                return false;
            }
        }
        return true;
    }
};

## Time Complexity
## Space Complexity
# Miscellaneous
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