Which programming languages is Number of Islands available in?

This code example is available in C++, C, Python. Use the language tabs above the code viewer to switch between implementations.

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Number of Islands

Q: How do I run this code?

Copy the code using the copy button, paste it into a file with the correct extension (.c, .java, .cpp, or .py), then compile and run it using the appropriate compiler or interpreter for the language.

Counts the number of islands in a grid where '1' is land and '0' is water using DFS.

number_islands.cpp

#include <iostream>
#include <vector>
using namespace std;

void dfs(int i, int j, vector<vector<char>>& g) {
    if (i < 0 || j < 0 || i >= g.size() || j >= g[0].size() || g[i][j] == '0')
        return;
    g[i][j] = '0';
    dfs(i + 1, j, g);
    dfs(i - 1, j, g);
    dfs(i, j + 1, g);
    dfs(i, j - 1, g);
}

int main() {
    cout << "INSTRUCTIONS: Enter dimensions N and M, then the grid row by row." << endl;
    int n, m;
    cin >> n >> m;
    vector<vector<char>> grid(n, vector<char>(m));
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            cin >> grid[i][j];

    int count = 0;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            if (grid[i][j] == '1') {
                count++;
                dfs(i, j, grid);
            }

    cout << count;
}

Number of Islands — Free C++, C, Python Code Example

Counts the number of islands in a grid where '1' is land and '0' is water using DFS. This free code example is available in C++, C, Python and can be copied and run immediately — no account or signup required. Use the language tabs above to switch between implementations.

How to Use This Code

Select your language — click the language tab (C, Java, C++, or Python) above the code viewer.
Copy the code — use the copy button in the top-right corner of the code block.
Run it — paste into a file with the correct extension (.c, .java, .cpp, .py), compile, and run using your terminal or IDE.
Follow the on-screen instructions in the terminal to provide any required inputs.

Frequently Asked Questions

What does this program do?

Counts the number of islands in a grid where '1' is land and '0' is water using DFS.

Which languages is it available in?

Available in C++, C, Python. Switch between implementations using the tabs at the top of the code viewer.

How do I run this code?

Copy the code, save it with the right file extension (.c, .java, .cpp, or .py), then compile or run it with your installed compiler or interpreter (GCC, JDK, G++, Python 3).

Is this code free?

Yes — free to view, copy, and use. No account required.

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#include <iostream> #include <vector> using namespace std; void dfs(int i, int j, vector<vector<char>>& g) { if (i < 0 || j < 0 || i >= g.size() || j >= g[0].size() || g[i][j] == '0') return; g[i][j] = '0'; dfs(i + 1, j, g); dfs(i - 1, j, g); dfs(i, j + 1, g); dfs(i, j - 1, g); } int main() { cout << "INSTRUCTIONS: Enter dimensions N and M, then the grid row by row." << endl; int n, m; cin >> n >> m; vector<vector<char>> grid(n, vector<char>(m)); for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) cin >> grid[i][j]; int count = 0; for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) if (grid[i][j] == '1') { count++; dfs(i, j, grid); } cout << count; }

How to Use This Code

Select your language — click the language tab (C, Java, C++, or Python) above the code viewer.

Copy the code — use the copy button in the top-right corner of the code block.

Run it — paste into a file with the correct extension (.c, .java, .cpp, .py), compile, and run using your terminal or IDE.

Follow the on-screen instructions in the terminal to provide any required inputs.

Frequently Asked Questions

What does this program do?

Counts the number of islands in a grid where '1' is land and '0' is water using DFS.

Which languages is it available in?

Available in C++, C, Python. Switch between implementations using the tabs at the top of the code viewer.

How do I run this code?

Copy the code, save it with the right file extension (.c, .java, .cpp, or .py), then compile or run it with your installed compiler or interpreter (GCC, JDK, G++, Python 3).

Is this code free?

Yes — free to view, copy, and use. No account required.