Correct code is nice

2 files changed, 20 insertions, 30 deletions

diff --git a/labb3/tiles/TileList.cpp b/labb3/tiles/TileList.cpp
index 88bdc21..c403de3 100644
--- a/labb3/tiles/TileList.cpp
+++ b/labb3/tiles/TileList.cpp
@@ -7,19 +7,20 @@ TileList::TileList()
 }
 
 TileList::~TileList()
-{delete tiles;
+{
+    delete tiles;
 }
 
 void TileList::addTile(Tile tile)
 {
-    // O(1) amortized
+    // O(1) (amortized)
     if (amount_tiles == cur_size) {
         // reached size limit, so allocate new array and move the old tiles
-        Tile *expanded_tiles = new Tile[cur_size + INCREASE_SIZE];
-        for (int i = 0; i < cur_size; i++) {
+        cur_size *= 2;
+        Tile *expanded_tiles = new Tile[cur_size];
+        for (int i = 0; i < amount_tiles; i++) {
             expanded_tiles[i] = tiles[i];
         }
-        cur_size += INCREASE_SIZE;
         delete tiles;
         tiles = expanded_tiles;
     }
@@ -37,18 +38,7 @@ void TileList::drawAll(QGraphicsScene *scene) const
 int TileList::indexOfTopTile(int x, int y) const
 {
     // O(n)
-    for (int i = 0; i < amount_tiles; i++) {
-        if ((tiles + i)->contains(x, y)) {
-            return i;
-        }
-    }
-    return -1;
-}
-
-int TileList::indexOfBottomTile(int x, int y) const
-{
-    // O(n)
-    for (int i = amount_tiles - 1; i >= 0; i--) {
+    for (int i = amount_tiles - 1; i >= 0; --i) {
         if ((tiles + i)->contains(x, y)) {
             return i;
         }
@@ -58,7 +48,7 @@ int TileList::indexOfBottomTile(int x, int y) const
 
 void TileList::shiftRight(int start, int end)
 {
-    // e.g. length=5, start=1, end=4:
+    // e.g. amount_tiles=6, start=1, end=4:
     // 0 1 2 3 4 5
     // 0 1 1 2 3 5
     // O(n)
@@ -69,11 +59,11 @@ void TileList::shiftRight(int start, int end)
 
 void TileList::shiftLeft(int start, int end)
 {
-    // e.g. length=5, start=4, end=1:
+    // e.g. amount_tiles=6, start=4, end=1:
     // 0 1 2 3 4 5
     // 0 2 3 4 4 5
     // O(n)
-    for (int i = start; i < end; i++) {
+    for (int i = end; i < start; i++) {
         tiles[i] = tiles[i + 1];
     }
 }
@@ -91,7 +81,7 @@ void TileList::raise(int x, int y)
         return;
     }
     Tile tmpTile = tiles[index];
-    shiftLeft(index, amount_tiles - 1);
+    shiftLeft(amount_tiles - 1, index);
     tiles[amount_tiles - 1] = tmpTile;
 }
 
@@ -102,7 +92,7 @@ void TileList::lower(int x, int y)
     // 0 0 1 2 4 5  3
     // 3 0 1 2 4 5  -
     // O(n)
-    int index = indexOfBottomTile(x, y);
+    int index = indexOfTopTile(x, y);
     if (index == -1 || index == 0) {
         // no tile found, or tile is already at bottom
         return;
@@ -114,10 +104,14 @@ void TileList::lower(int x, int y)
 
 void TileList::remove(int x, int y)
 {
+    //     V
+    // 0 1 2 3 4 5
+    // 0 1 3 4 5 5
+    // 0 1 3 4 5 x
     // O(n)
     int index;
-    if ((index = indexOfBottomTile(x, y)) != -1) {
-        shiftLeft(index, amount_tiles - 1);
+    if ((index = indexOfTopTile(x, y)) != -1) {
+        shiftLeft(amount_tiles - 1, index);
         amount_tiles--;
     }
 }
@@ -127,7 +121,7 @@ void TileList::removeAll(int x, int y)
     // O(n^2)
     int index;
     while ((index = indexOfTopTile(x, y)) != -1) {
-        shiftLeft(index, amount_tiles - 1);
+        shiftLeft(amount_tiles - 1, index);
         amount_tiles--;
     }
 }
diff --git a/labb3/tiles/TileList.h b/labb3/tiles/TileList.h
index 865823f..10cfdfb 100644
--- a/labb3/tiles/TileList.h
+++ b/labb3/tiles/TileList.h
@@ -16,7 +16,7 @@ public:
     ~TileList(); // deallocate the tile list
     void addTile(Tile tile); // add a tile to the tile list, possibly reallocating
     void drawAll(QGraphicsScene *scene) const; // draw all tiles to `scene`
-    int indexOfTopTile(int x, int y) const;
+    int indexOfTopTile(int x, int y) const; // return index of top tile at (x, y)
     void lower(int x, int y); // move the top tile at (x, y) to the bottom
     void raise(int x, int y); // move the bottom tile at (x, y) to the top
     void remove(int x, int y); // remove the top tile at (x, y)
@@ -24,14 +24,10 @@ public:
 
 private:
     static const int INITIAL_SIZE = 10;  // the initial size
-    static const int INCREASE_SIZE = 10; // how much the size is increased when
-                                         // it's needed
     int cur_size = 0;                    // current size of array
     int amount_tiles;                    // number of active tiles in array
     Tile *tiles;                         // the array
 
-    int indexOfBottomTile(int x, int y) const;
-
     /*
      * shiftRight and shiftLeft move a group of tiles either right or left
      * in the internal array.