HW4: done

chess_paths/chess_paths.c

@@ -217,12 +217,12 @@ void knight_positions(struct search_status* s, struct piece_position* p) {
 
     if (row >= 1 && col >= 2)            consider(s, col - 2, row - 1);
     if (row >= 2 && col >= 1)            consider(s, col - 1, row - 2);
-    if (row >= 2 && col <= cs - 1)       consider(s, col + 1, row - 2);
+    if (row >= 2 && col + 1 <= cs)       consider(s, col + 1, row - 2);
-    if (row >= 1 && col <= cs - 2)       consider(s, col + 2, row - 1);
+    if (row >= 1 && col + 2 <= cs)       consider(s, col + 2, row - 1);
-    if (row <= rs - 1 && col <= cs - 2)  consider(s, col + 2, row + 1);
+    if (row + 1 <= rs && col + 2 <= cs)  consider(s, col + 2, row + 1);
-    if (row <= rs - 2 && col <= cs - 1)  consider(s, col + 1, row + 2);
+    if (row + 2 <= rs && col + 1 <= cs)  consider(s, col + 1, row + 2);
-    if (row <= rs - 2 && col >= 1)       consider(s, col - 1, row + 2);
+    if (row + 2 <= rs && col >= 1)       consider(s, col - 1, row + 2);
-    if (row <= rs - 1 && col >= 2)       consider(s, col - 2, row + 1);
+    if (row + 1 <= rs && col >= 2)       consider(s, col - 2, row + 1);
 }
 
 void bishop_positions(struct search_status* s, struct piece_position* p) {

roadmap/Makefile

@@ -1,6 +1,6 @@
 OBJECTS = roadmap.o
 CFLAGS=-Wall -g
-CXXFLAGS=-Wall -g
+CXXFLAGS=-Wall -g -std=c++11
 SHELL=/bin/bash
 
 TIMEOUT=8

roadmap/roadmap.cpp

@@ -1,26 +1,28 @@
+// vim: set ts=4 sw=4 et tw=80:
+
 #include "roadmap.h"
+#include <iostream>
 #include <map>
 #include <set>
+#include <deque>
+#include <stack>
 
-using std::map;
+using namespace std;
-using std::set;
 
 class ConcreteRoadMap : public AbstractRoadMap {
-private:
+    private:
-  int cities;
-
         map< string, set<string> > adj;
 
         /*
-   * Adds in the map for key city1 a new set with city2 inside if there is no
+         * Adds in the map for key city1 a new set with city2 inside if there is
-   * prior set, otherwise it appends city2 into the existing set
+         * no prior set, otherwise it appends city2 into the existing set
          */
         void addPair(const string& city1, const string& city2) {
             this->adj[city1].insert(city2);
         }
 
-public:
+    public:
-  ConcreteRoadMap() : adj(), cities(0) {};
+        ConcreteRoadMap() : adj() {};
 
         void addRoad(const string& city1, const string& city2) override {
             addPair(city1, city2);
@@ -39,6 +41,113 @@ public:
 
         int neighborCountForCity(const string& city) const override {
             auto i = this->adj.find(city);
+            if (i == adj.end()) return -1;
             return i->second.size();
         }
+
+        bool hasLoop() const override {
+            stack< std::pair<string, string> > s;
+            set<string> discovered;
+            bool search_comp;
+
+            for (auto itr = adj.begin(); itr != adj.end(); ++itr) {
+                search_comp = true;
+                s.push(std::pair<string, string>(itr->first, itr->first));
+                while (!s.empty()) {
+                    const std::pair<string, string> v = s.top();
+#if DEBUG
+                    std::cout << "Front is: " << v.first << " with parent " <<
+                        v.second << "\n";
+#endif
+                    s.pop();
+                    if (discovered.find(v.first) == discovered.end()) {
+                        search_comp = false;
+                        discovered.insert(v.first);
+                        const auto i = this->adj.find(v.first);
+                        const auto set = i->second;
+                        for (auto j = set.begin(); j != set.end(); ++j) {
+                            if (*j != v.second) {
+#if DEBUG
+                                cout << "Neighbor: " << *j << " parent: " <<
+                                    v.first << "\n";
+#endif
+                                s.push(std::pair<string, string>(*j,
+                                            v.first));
+                            }
+                        }
+                    } else if (!search_comp) {
+                        // cout << v.first << " is discovered\n";
+                        return true;
+                    }
+                }
+            }
+            return false;
+        }
+
+        bool reachable(const string& c1, const string& c2) const override {
+            if (adj.find(c1) == adj.end() ||
+                    adj.find(c2) == adj.end()) {
+                return false;
+            }
+
+            deque<string> s;
+            set<string> discovered;
+            s.push_back(c1);
+            while (!s.empty()) {
+                const string& v = s.front();
+                if (v == c2) return true;
+                s.pop_front();
+
+                discovered.insert(v);
+                const auto i = this->adj.find(v);
+                const auto set = i->second;
+                for (auto j = set.begin(); j != set.end(); ++j) {
+                    if (discovered.find(*j) == discovered.end()) {
+                        s.push_back(*j);
+                    }
+                }
+            }
+            return false;
+        }
+
+        int countIslands() const override {
+            int islands = 0;
+            bool first;
+
+            stack< std::pair<string, string> > s;
+            set<string> discovered;
+
+            for (auto itr = adj.begin(); itr != adj.end(); ++itr) {
+                s.push(std::pair<string, string>(itr->first, itr->first));
+                first = true;
+                while (!s.empty()) {
+                    const std::pair<string, string>& v = s.top();
+                    s.pop();
+                    if (discovered.find(v.first) == discovered.end()) {
+
+                        if (first) {
+                            islands++;
+                        }
+
+                        discovered.insert(v.first);
+                        const auto i = this->adj.find(v.first);
+                        const auto set = i->second;
+
+                        for (auto j = set.begin(); j != set.end(); ++j) {
+                            if (*j != v.second) {
+                                s.push(std::pair<string, string>(*j, v.first));
+                            }
+                        }
+                    }
+
+                    first = false;
+                }
+            }
+
+            return islands;
+        }
 };
+
+AbstractRoadMap* createRoadMap() {
+    return new ConcreteRoadMap();
+}