3898. Find the Degree of Each Vertex

You are given a 2D integer array matrix of size n x n representing the adjacency matrix of an undirected graph with n vertices labeled from 0 to n - 1.

• matrix[i][j] = 1 indicates that there is an edge between vertices i and j.
• matrix[i][j] = 0 indicates that there is no edge between vertices i and j.

The degree of a vertex is the number of edges connected to it.

Return an integer array ans of size n where ans[i] represents the degree of vertex i.

class Solution {
public:
    vector<int> findDegrees(vector<vector<int>>& matrix) {
        int n = matrix.size();
        vector<int> res(n);
        for(int i = 0; i < n; i++) res[i] = accumulate(begin(matrix[i]), end(matrix[i]), 0);
        return res;
    }
};