Checking if an element exists in a 2D vector

25 Sep 2023

std::vector<std::vector<int>> matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
int target = 5;
bool elementExists = false;

To check if the target element exists in the matrix, we can iterate over each row and column using nested loops and compare each element with the target.

for (int i = 0; i < matrix.size(); i++) {
    for (int j = 0; j < matrix[i].size(); j++) {
        if (matrix[i][j] == target) {
            elementExists = true;
            break;
        }
    }
    if (elementExists) {
        break;
    }
}

Here, we use a boolean variable elementExists to keep track of whether the element has been found or not. If the element is found, we set elementExists to true and break out of both loops.

Finally, we can check the value of elementExists to determine if the element exists in the 2D vector.

if (elementExists) {
    std::cout << "Element exists in the vector." << std::endl;
} else {
    std::cout << "Element does not exist in the vector." << std::endl;
}

By using this approach, we can easily check if an element exists in a 2D vector.