[STL] 2차원 벡터와 맵(해시테이블)

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2023/03/13 11:39

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C++

[STL] 2차원 벡터와 맵(해시테이블)

int main() {
    int n, m;
    cin >> n >> m;
    vector<vector<int>> v(n, vector<int>(m));

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> v[i][j];
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cout << v[i][j] << " ";
        }
        cout << '\n';
    }
}
C++
복사

v.resize(n, vector<int>(m));

int main() {
    int n, m;
    cin >> n >> m;
		v.resize(n, vector<int>(m));

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> v[i][j];
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cout << v[i][j] << " ";
        }
        cout << '\n';
    }
}
C++
복사

matrix_t 으로 선언할 경우

typedef vector<vector<int>> matrix_t;

matrix_t v;

int main() {
    int n, m;
    cin >> n >> m;
		v.resize(n, vector<int>(m));

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> v[i][j];
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cout << v[i][j] << " ";
        }
        cout << '\n';
    }
}
C++
복사

2차원 벡터의 사이즈

vector<vector<int>> arr = { {1, 2, 3}, {4, 5, 6} };

// 행 (row)
int row_count = arr.size(); // result: 2

// 열 (column)
int col_count = arr[0].size();  // result: 3
C++
복사

HashMap

#include <map>
#include <utility>

int main() {
	map<int, string> mymap;
	int n;
	cin >> n;

	for (int i = 0; i < n; i++) {
		int num;
		cin >> num;
		string str;
		cin >> str;
		mymap[num] = str;
	}

	for (auto item: map) {
		cout << item.first << ": " << item.second << '\n';
	}
}
C++
복사