Module 15: Get Strings from the Grid

a.c

@@ -37,7 +37,14 @@ ostream& operator<<(ostream& os, const Point& p) {  // for printing
 //-Span
 struct Span {
   Span(Point p, int l, bool v) : point(p), len(l), vert(v) {}
-
+  Point GetPoint(int i) const {
+    assert(i >= 0 && i < len);
+    if (vert) {
+      return Point(point.row + i, point.col);
+    } else {
+      return Point(point.row, point.col + i);
+    }
+  }
   friend ostream& operator<<(ostream& os, const Span& s);
 
   Point point;
@@ -112,7 +119,6 @@ public:
   }
   void CreatePatternHash(Word* w) {
     int len = w->len();
-    if (len > 7) return;  // avoid load of long words
     int num_patterns = 1 << len;  // create 2^len patterns
     // cout << "PATTERN HASH on " << w->word << "\n";
     for (int i=0; i<num_patterns; i++) {
@@ -127,7 +133,7 @@ public:
       word_map_[temp].push_back(w);
     }
   }
-  void ReadFromFile(string filename) {
+  void ReadFromFile(string filename, int max_size) {
     ifstream f;
     f.open(filename);
     while (f.is_open() && !f.eof()) {  // check for the file!
@@ -140,9 +146,11 @@ public:
         if (line[len - 1] == '\r') {
           line = line.substr(0, len - 1);
         }
-        Word* w = new Word(line);
-        words_.push_back(w);  // Word would be allocated on the heap
-        CreatePatternHash(w);
+        if (len <= max_size) {
+          Word* w = new Word(line);
+          words_.push_back(w);  // Word would be allocated on the heap
+          CreatePatternHash(w);
+        }
       }
     }
     cout << "Read " << words_.size() << " words from file '"
@@ -172,6 +180,7 @@ struct Grid {
       return lines[0].size();
     }
   }
+  int max_size() const { return max(rows(), cols()); }
   // Returns character value of the box at point 'p'
   // 'p' must be in bounds
   char box(const Point& p) const {
@@ -193,6 +202,17 @@ struct Grid {
   bool in_bounds(const Point& p) const {
     return (p.row >= 0 && p.row < rows() && p.col >= 0 && p.col < cols());
   }
+  // Fills in attributes of the string
+  string GetString(const Span& s) const {
+    int len = s.len;
+    string temp;
+    temp.resize(len);
+    for (int i=0; i<len; i++) {
+      Point p = s.GetPoint(i);
+      temp[i] = box(p);
+    }
+    return temp; 
+  }
   // Next increments the point across the grid, one box at a time
   // Returns true if point is still in bounds
   bool Next(Point& p, bool vert) {
@@ -211,6 +231,27 @@ struct Grid {
     }
     return in_bounds(p);
   }
+  // NextStopAtWrap is like "Next" except it returns false at every wrap
+  // Returns true if we stay on the same line
+  bool NextStopAtWrap(Point& p, bool vert) {
+    bool wrap = false;
+    if (vert) {
+      p.row++;
+      if (p.row >= rows()) {
+        p.row = 0;
+        p.col++;
+        wrap = true;
+      }    
+    } else {
+      p.col++;
+      if (p.col >= cols()) {
+        p.col = 0;
+        p.row++;
+        wrap = true;
+      }
+    }
+    return !wrap;
+  }
   void FillSpans(bool vert) {
     Point p;
     // check all spans
@@ -224,10 +265,11 @@ struct Grid {
      // cout << "SPAN START: " << p << "\n";
       
       int len = 0;
+      bool keep_going = false;
       do {
-        Next(p, vert);
+        keep_going = NextStopAtWrap(p, vert);
         len++;
-      } while (in_bounds(p) && !is_block(p));    
+      } while (keep_going && !is_block(p));    
       //cout << "END OF SPAN!!! len=" << len << "\n";
       spans.push_back(Span(startp, len, vert));
     }
@@ -258,7 +300,8 @@ struct Grid {
   void Print() const {
     cout << "Grid: " << name
          << " (rows=" << rows()
-         << ", cols=" << cols() << ")\n";
+         << ", cols=" << cols()
+         << ", max_size=" << max_size() << ")\n";
     for (string s : lines) {
       cout << "  " << s << "\n";
     }
@@ -266,7 +309,7 @@ struct Grid {
   void PrintSpans() const {
     cout << "Spans:\n";
     for (const Span& s : spans) {
-      cout << "  " << s << "\n";
+      cout << "  " << s << " " << GetString(s) << "\n";
     }
   }
   string name; // strings are initialized empty
@@ -275,13 +318,13 @@ struct Grid {
 };
 
 int main() {
-  Library lib;
-  lib.ReadFromFile("top_12000.txt");
-  
   Grid grid("MY GRID");
   grid.LoadFromFile("test");
   grid.Check();
   grid.Print();
   grid.FillSpans();
   grid.PrintSpans();
+  
+  Library lib;
+  lib.ReadFromFile("top_12000.txt", grid.max_size());
 }