put these back as well

Author: lrvideckis

library/graphs/bcc_callback.hpp

@@ -44,7 +44,7 @@
 void bcc(const auto& g, auto f) {
   int n = sz(g), q = 0, s = 0;
   vi t(n), st(n);
-  auto dfs = [&](auto dfs, int u) {
+  auto dfs = [&](auto dfs, int u) -> int {
     int l = t[u] = ++q;
     for (int v : g[u]) {
       int siz = s, lu = 0;

library/graphs/euler_path.hpp

@@ -16,7 +16,7 @@
 vector<pii> euler_path(auto& g, int m, int s) {
   vi vis(m);
   vector<pii> path;
-  auto dfs = [&](auto dfs, int u, int eu) {
+  auto dfs = [&](auto dfs, int u, int eu) -> void {
     while (!empty(g[u])) {
       auto [v, ev] = g[u].back();
       g[u].pop_back();

library/graphs/hopcroft_karp.hpp

@@ -43,7 +43,7 @@ struct hopcroft_karp {
         }
       }
       if (!found) break;
-      auto dfs = [&](auto dfs, int u) {
+      auto dfs = [&](auto dfs, int u) -> bool {
         for (int v : g[u]) {
           int w = to_l[v];
           if (w == -1 ||

library/graphs/scc.hpp

@@ -11,7 +11,7 @@
 auto scc(const auto& g) {
   int n = sz(g), num_sccs = 0, q = 0, s = 0;
   vi scc_id(n, -1), tin(n), st(n);
-  auto dfs = [&](auto dfs, int u) {
+  auto dfs = [&](auto dfs, int u) -> int {
     int low = tin[u] = ++q;
     st[s++] = u;
     for (int v : g[u])

library/graphs/uncommon/cuts.hpp

@@ -19,7 +19,7 @@
 auto cuts(const auto& g, int m) {
   int n = sz(g), num_bccs = 0, q = 0, s = 0;
   vi bcc_id(m, -1), is_cut(n), tin(n), st(m);
-  auto dfs = [&](auto dfs, int u, int p) {
+  auto dfs = [&](auto dfs, int u, int p) -> int {
     int low = tin[u] = ++q;
     for (auto [v, e] : g[u]) {
       assert(u != v);

library/trees/centroid_decomp.hpp

@@ -16,7 +16,7 @@ void centroid(auto& g, auto f) {
       }
     return 2 * siz[u] >= n ? siz[p] = n - siz[u], u : -1;
   };
-  auto dfs = [&](auto dfs, int u, int p, int n) {
+  auto dfs = [&](auto dfs, int u, int p, int n) -> void {
     f(u = ctd(ctd, u, u, n), p);
     for (int v : g[u])
       erase(g[v], u), dfs(dfs, v, u, siz[v]);