Method lca

code/graph/tarjan_olca.test.cpp:122–129

  }

  int lca(int a, int b) {
    a = label[a];
    b = label[b];
    int x = start[a],
      y = start[b];
    if (x > y) swap(x, y);
    return orig[st.query(x, y).x];
  }
};

void test() {