#include <iostream>
#include <vector>

int main() {
	std::vector<std::vector<int>> arr = {{100, 120, 200}, {110, 140, 300}, {130, 170, 400}};
	arr[1][1] = 0;
	for(const auto& row: arr) {
	    for(const auto& elem: row)
	        std::cout << elem << " ";
	    std::cout << std::endl;
	}
}