Алгоритм Куна

bool dfs(vector<vector<int>> &graphA, int vFromA, vector<int> &visited, vector<int> &pairFromA) {
    visited[vFromA] = 1;

    for (int vFromB : graphA[vFromA]) {
        int &toFromA = pairFromA[vFromB];

        if (toFromA == -1 || !visited[toFromA] && dfs(graphA, toFromA, visited, pairFromA)) {
            toFromA = vFromA;
            return 1;
        }
    }

    return 0;
}

vector<int> kuhn(vector<vector<int>> &graphA, int vertexCountB) {
    vector<int> pairFromA(vertexCountB, -1);

    for (int vFromA = 0; vFromA < graphA.size(); vFromA++) {
        vector<int> visited(graphA.size());
        dfs(graphA, vFromA, visited, pairFromA);
    }

    return pairFromA;
}