From 065abf63fd79397552347c8f2d587cd99426a309 Mon Sep 17 00:00:00 2001
From: Kirill Petrashin <kirill8201@yandex.ru>
Date: Thu, 26 Mar 2026 13:50:12 +0300
Subject: Add ppq_insert() return codes + fix breadth_first_search_4dir()

---
 path.c           |  7 ++++---
 priority_queue.c | 10 +++++-----
 priority_queue.h |  3 +++
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/path.c b/path.c
index 6f00ee8..e32610b 100644
--- a/path.c
+++ b/path.c
@@ -49,8 +49,9 @@ Path breadth_first_search_path_4dir(Map map, size_t width, size_t height, Positi
             /* The Russian constitution doesn't allow walking on walls */
             if (map[na[i].y][na[i].x] == WALL) continue;
 
-            ppq_insert(&frontier, na[i], 0);
-            path[na[i].y][na[i].x].parent = cur;
+            if (ppq_insert(&frontier, na[i], 0) != PPQ_INSERT_ALREADY) {
+                path[na[i].y][na[i].x].parent = cur;
+            }
         }
         
         if (should_anim) {
@@ -91,7 +92,7 @@ Path breadth_first_search_path_8dir(Map map, size_t width, size_t height, Positi
             /* The Russian constitution doesn't allow walking on walls */
             if (map[na[i].y][na[i].x] == WALL) continue;
 
-            if (ppq_insert(&frontier, na[i], 0) != 3) {
+            if (ppq_insert(&frontier, na[i], 0) != PPQ_INSERT_ALREADY) {
                 path[na[i].y][na[i].x].parent = cur;
             }
         }
diff --git a/priority_queue.c b/priority_queue.c
index d4be6e2..6e74b22 100644
--- a/priority_queue.c
+++ b/priority_queue.c
@@ -20,7 +20,7 @@ int ppq_insert(PositionPQ **ppq, Position pos, size_t priority) {
 
     if ((*ppq) == NULL) {
         (*ppq) = ppq_new(pos, priority);
-        return 1;
+        return PPQ_INSERT_NEW;
     }
     
     PositionPQ *n = ppq_new(pos, priority);
@@ -28,7 +28,7 @@ int ppq_insert(PositionPQ **ppq, Position pos, size_t priority) {
     if (start->priority > priority) {
         n->next = start;
         start = n;
-        return 2;
+        return PPQ_INSERT_SUCCESS;
     }
 
     PositionPQ *temp = *ppq;
@@ -36,19 +36,19 @@ int ppq_insert(PositionPQ **ppq, Position pos, size_t priority) {
     while(temp->next != NULL && temp->next->priority <= priority) {
         if (temp->pos.x == pos.x && temp->pos.y == pos.y && temp->priority <= priority) {
             free(n);
-            return 3; /* pos is already in ppq with a fine priority */
+            return PPQ_INSERT_ALREADY;
         }
         temp = temp->next;
     }
     if (temp->pos.x == pos.x && temp->pos.y == pos.y && temp->priority <= priority) {
         free(n);
-        return 3; /* pos is already in ppq with a fine priority */
+        return PPQ_INSERT_ALREADY;
     }
 
     n->next = temp->next;
     temp->next = n;
 
-    return 4;
+    return PPQ_INSERT_SUCCESS;
 }
 
 Position ppq_pop(PositionPQ **ppq) {
diff --git a/priority_queue.h b/priority_queue.h
index 63e9bbc..13eea1a 100644
--- a/priority_queue.h
+++ b/priority_queue.h
@@ -19,6 +19,9 @@ typedef struct PositionPQNode_s PositionPQ;
 PositionPQ *ppq_new(Position pos, size_t priority);
 
 /* Insert a pos with priority into a given PositionPQ */
+#define PPQ_INSERT_SUCCESS 0
+#define PPQ_INSERT_NEW 1 /* ppq was NULL, created a new one */
+#define PPQ_INSERT_ALREADY 2 /* pos is already in ppq */
 int ppq_insert(PositionPQ **ppq, Position pos, size_t priority);
 
 /* Remove and return the position with the lowest priority */
-- 
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