Poll timeout/interrupt/memory-limit inside dive loops; fix pulling should_stop

cpp/rcspp/algorithm/greedy.hpp

@@ -90,7 +90,16 @@ class GreedyAlgorithm : public Algorithm<ResourceType, LabelContainerType> {
             // Note: do NOT keep a reference to path_.back() across pop_back() calls
             // (that'd be a dangling reference). Re-query path_.back() each loop.
             // try to extend the label greedily
+            //
+            // The sibling-switching backtrack below can enumerate many partial
+            // paths inside this single call, so poll should_stop() and the
+            // memory limit every 4096 steps.
+            size_t steps = 0;
             while (!path_.empty()) {
+                if ((++steps & 0xFFFU) == 0 &&
+                    (this->should_stop() || this->memory_limit_.is_exceeded())) {
+                    return;
+                }
                 bool extended = false;
                 while (extend_label(path_.back().first)) {
                     extended = true;  // successfully extended

cpp/rcspp/algorithm/improving_tabu_search.hpp

@@ -213,7 +213,16 @@ class ImprovingTabuSearch : public BacktrackingDiveAlgorithm<ResourceType, Label
     private:
         // ─── helpers ─────────────────────────────────────────────────────────
         bool dive_to_sink() {
+            // A single dive can enumerate exponentially many partial paths
+            // between main_loop()'s per-iteration checks — and each extension
+            // allocates a label — so poll should_stop() and the memory limit
+            // every 4096 steps.
+            size_t steps = 0;
             while (!this->path_.empty()) {
+                if ((++steps & 0xFFFU) == 0 &&
+                    (this->should_stop() || this->memory_limit_.is_exceeded())) {
+                    return false;
+                }
                 auto* current = this->path_.back().first;
                 if (current->get_end_node()->sink) {
                     return true;

cpp/rcspp/algorithm/pulling_dominance_algorithm.hpp

@@ -32,7 +32,7 @@ class PullingDominanceAlgorithm : public DominanceAlgorithm<ResourceType, LabelC
 
         void main_loop() override {  // NOLINT
             size_t i = 0;
-            while (number_of_labels() > 0 && i < this->params_.max_iterations) {
+            while (number_of_labels() > 0 && !this->should_stop(i)) {
                 // Periodic memory check (pulling: each iteration processes one node).
                 if (i > 0 && this->memory_limit_.effective_limit > 0 &&
                     i % this->params_.memory_check_interval == 0) {

cpp/rcspp/algorithm/tabu_search.hpp

@@ -139,7 +139,16 @@ class TabuSearchAlgorithm : public BacktrackingDiveAlgorithm<ResourceType, Label
         // ------------------------------------------------------------------
 
         bool dive_to_sink() {
+            // A single dive can enumerate exponentially many partial paths
+            // between main_loop()'s per-iteration checks — and each extension
+            // allocates a label — so poll should_stop() and the memory limit
+            // every 4096 steps.
+            size_t steps = 0;
             while (!this->path_.empty()) {
+                if ((++steps & 0xFFFU) == 0 &&
+                    (this->should_stop() || this->memory_limit_.is_exceeded())) {
+                    return false;
+                }
                 auto* current = this->path_.back().first;
                 if (current->get_end_node()->sink) {
                     return true;