CPP

how to initialized a 2d vector

To be used in DP problems:

vector<vector<int>>dp; //global init

dp = vector<vector<int>>(n,vector<int>(m,0)); // local init for test cases
where,
	n, m = dimensions of matrix

initialzing a 2d vector in cpp

  // Create a vector containing n row and m columns
  vector<vector<int> > vec( n , vector<int> (m, 0));  

2d vector initialization in cpp

vector<vector<int>> vec( n , vector<int> (m, 0));

where: n is number of ROWS,
	   m is number of COLUMNS
       
So result will be ( Let n = 2, m = 3 )
  	[[ 0, 0, 0],
     [ 0, 0, 0]]
     		   ( 2 x 3 )

initialize 2d vector of ints c++

auto M = 4;	// num of rows
auto N = 3; // num of cols in each row
auto default_value = 1; // default value of all int elements
std::vector<std::vector<int>> matrix(M, std::vector<int>(N, default_value));

how to make a 2d vector in c++

// Create a vector containing n 
//vectors of size m, all u=initialized with 0
vector<vector<int> > vec( n , vector<int> (m, 0));  

how to initialize 2d vector in c++

#include <iostream>
#include <vector>
#include <algorithm>
 
int main()
{
    std::vector<int> v = {2, 1, 3, 6, 7, 9, 8};
 
    int max = *max_element(v.begin(), v.end());
    int min = *min_element(v.begin(), v.end());
 
    std::cout << min << ", " << max << std::endl;        // 1, 9
 
    return 0;
}

2d vector c++ declaration

vector< vector<int>> a(rows, vector<int> (cols));

initializing 2d vector

// to make (n rows x m columns) 2D array, all initialized 
// with value 'k' (typeof(k) = T)
vector<vector<T>> vec( n , vector<T> (m, k)); 

how to initialize 2d vector in c++

#include<vector>
#include<algorithm>

// all the  std and main syntax ofcourse.

vector<int> pack = {1,2,3} ;

// To add at the END
pack.push_back(6);       // {1,2,3,6}

//  OR
// To add at BEGGINING 
pack.insert(pack.begin(),6) 	// {6,1,2,3,}		

initialize 2D vector

vector<vector<int> >    v2(8, vector<int>(5));

create a 2d vector in c++

// CPP program
#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n = 3;
    int m = 4;
 
    /*
    We create a 2D vector containing "n"
    elements each having the value "vector<int> (m, 0)".
    "vector<int> (m, 0)" means a vector having "m"
    elements each of value "0".
    Here these elements are vectors.
    */
    vector<vector<int>> vec( n , vector<int> (m, 0));
 
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cout << vec[i][j] << " ";
        }
        cout<< endl;
    }
     
    return 0;
}

how to initialize 2d vector in c++

#include<vector>
#include<algorithm>      //**********Have to include THIS...OTHERWISE

sort( vectorName.begin(),vectorName.end() ) ;

how to create 2d array using vector in c++

vector<vector<int>> vec(N, vector<int> (M, INT_MAX));

Explanation::
vector<vector<int>> -- will take the formed container
N -- Think like row of 2d Matrix
vector<int> (M, INT_MAX) -- In each row, there is again a vector associated with it, 
that will formed 2d array.

initialising 2d vector

// Initializing 2D vector "vect" with 
// values 
vector<vector<int> > vect{ { 1, 2, 3 }, 
                           { 4, 5, 6 }, 
                           { 7, 8, 9 } };