diff options
Diffstat (limited to 'Graph/lca.cpp')
| -rw-r--r-- | Graph/lca.cpp | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/Graph/lca.cpp b/Graph/lca.cpp index d02598f..38d972e 100644 --- a/Graph/lca.cpp +++ b/Graph/lca.cpp @@ -1,5 +1,5 @@ -struct lca { - int d[MN], L[MN][20]; +namespace lca { + int d[MX], L[MX][20]; void dfs(vector<int> * G, int u = 1, int p = 0) { d[u] = d[p] + 1, L[u][0] = p; for (int i = 0; i < 18 && L[u][i]; i++) L[u][i + 1] = L[L[u][i]][i]; @@ -7,9 +7,12 @@ struct lca { } int lca(vector<int> * G, int u, int v) { if (d[u] > d[v]) swap(u, v); - for (int i = 18; i >= 0; i--) if (d[v] - (1 << i) >= d[u]) v = L[v][i]; + for (int i = 18; i >= 0; --i) if (d[v] - (1 << i) >= d[u]) v = L[v][i]; if (u == v) return u; - for (int i = 18; i >= 0; i--) if (L[u][i] && L[u][i] != L[v][i]) u = L[u][i], v = L[v][i]; + for (int i = 18; i >= 0; --i) if (L[u][i] && L[u][i] != L[v][i]) u = L[u][i], v = L[v][i]; return L[u][0]; } + inline int dist(vector<int> * G, int u, int v) { + return d[u]+d[v]-2*d[lca(G, u, v)]; + } } |