C++二维数组每行元素一致性检测算法及代码需求

Got it, let's work through this problem together. You need a C++ solution that scans a 2D matrix and returns 1 if any row has non-identical elements, and 0 if every row's elements are all the same.

Approach #

The core idea here is to optimize for early termination—no need to check the entire matrix once we find a row that fails the test. Here's the step-by-step logic:

• Iterate over each row in the matrix.
• For each row, take the first element as a reference value (we’ll handle edge cases like empty rows/matrix too).
• Compare every other element in the row to this reference.
• If any element doesn’t match the reference, immediately return 1—no need to check further rows.
• If all rows pass the check (all elements in every row are identical), return 0.

C++ Code Implementation #

Here's a clean, efficient implementation with comments:

#include <vector>

int checkUniformRows(const std::vector<std::vector<int>>& matrix) {
    // Handle edge case: empty matrix
    if (matrix.empty()) {
        return 0; // Adjust this if your requirement for empty input differs
    }

    for (const auto& row : matrix) {
        // Handle edge case: empty row (treat as uniform here)
        if (row.empty()) {
            continue;
        }

        int reference = row[0];
        for (size_t i = 1; i < row.size(); ++i) {
            if (row[i] != reference) {
                // Found a non-uniform row, exit early
                return 1;
            }
        }
    }

    // All rows are fully uniform
    return 0;
}

// Example usage
#include <iostream>
int main() {
    // Example 1 matrix (returns 1)
    std::vector<std::vector<int>> matrix1 = {
        {0, 1, 2, 3},
        {0, 2, 1, 4}, // This row has mismatched elements (1 vs 4)
        {4, 2, 6, 3}
    };
    std::cout << checkUniformRows(matrix1) << std::endl; // Output: 1

    // Example of a fully uniform matrix (returns 0)
    std::vector<std::vector<int>> matrix2 = {
        {5,5,5},
        {2,2},
        {9,9,9,9}
    };
    std::cout << checkUniformRows(matrix2) << std::endl; // Output: 0

    return 0;
}

Example Breakdown #

Let’s walk through your first example:

Example1矩阵：
0 1 2 3
0 2 1 4
4 2 6 3

When the code processes the second row ({0,2,1,4}), it takes 0 as the reference value. As soon as it hits 2 (which doesn’t match 0), or later 1 and 4, it immediately stops checking and returns 1—this saves unnecessary computation on the rest of the matrix.

For a matrix where every row’s elements are identical, the code will loop through all rows, confirm all elements match the first in their row, and finally return 0.

内容的提问来源于stack exchange，提问作者Toms lns