vector<vector<int>> 简单知识介绍

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
bool cmp(const vector<int> &a, const vector<int> &b) {
    return a[1] < b[1];
}
int main()
{
    vector<vector<int>> vet;
    int RR, CC;
    cin >> RR >> CC;
    for (int i = 0; i<RR; i++)        //输入数据
    {
        vector<int> myvector;
        for (int j = 0; j<CC; j++)
        {
            int tempVal = 0;
            cin >> tempVal;
            myvector.push_back(tempVal);
        }
        vet.push_back(myvector);
    }
    cout << vet.size() << endl;    //计算行数
    cout << vet[0].size() << endl; //计算列数
    sort(vet.begin(), vet.end());  //仅对第一列进行排序
    for (int i = 0; i < RR; i++)
    {

        for (int j = 0; j < CC; j++)
        {
            cout << vet[i][j] << " ";
        }
        cout << endl;
    }
    sort(vet.begin(), vet.end(),cmp);// 利用cmp可以根据其他列排序。
    for (int i = 0; i < RR; i++)
    {

        for (int j = 0; j < CC; j++)
        {
            cout << vet[i][j] << " ";
        }
        cout << endl;
    }
    system("pause");
    return 0;
}

 方法二：插入的不同方法

#include<iostream>
#include<vector>
#include<set>
#include<algorithm>
using namespace std;
int main()
{
	int r = 2;
	int c = 3;
	vector<vector<int>> vet(r,vector<int>(c));
	
	
	for (int n = 0; n<r*c; n++) 
	{
		vet[n / c][n%c] = 45;
	}
	for (int n = 0; n<r*c; n++)
	{
		cout << vet[n / c][n%c] << endl;
	}
	system("pause");
	return 0;
}