update ch2

Author: AceCoooool

README.md

@@ -3,15 +3,13 @@ Algorithms, 4th edition textbook code (using c++)
 
 **Note：**
 
-**（the code can run, but may not well --- I will modify these in the next cycle）**
-
 1. based on STL Library
 2. using C++14
 3. **Not support** drawing
 4. **Bug: ** ① const object (many member function forget to add const) 
 4. Welcome to point out the error, and pull better code
 
-## How to run demo
+## Tutorial: run demo code
 
 ### terminal
 

ch2/10_Quick/main.cpp

@@ -4,8 +4,16 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; quicksorts them; 
+ * and prints them to standard output in ascending order. 
+ * Shuffles the array and then prints the strings again to
+ * standard output, but this time, using the select method.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/11_Quick3way/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; 3-way
+ * quicksorts them; and prints them to standard output in ascending order. 
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/12_QuickX/main.cpp

@@ -4,8 +4,15 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; quicksorts them
+ * (using an optimized version of 2-way quicksort); 
+ * and prints them to standard output in ascending order. 
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/13_QuickBentleyMcIlroy/main.cpp

@@ -4,8 +4,15 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; quicksorts them
+ * (using an optimized version of quicksort);
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/words3.txt");
+    ifstream file("./data/words3.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/14_TopM/main.cpp

@@ -23,7 +23,7 @@ int main() {
     int m = 5;
     auto f = [](Transaction &a1, Transaction &a2) { return a1.getamount() > a2.getamount(); };
     MinPQ<Transaction> pq(f);
-    fstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tinyBatch.txt");
+    fstream file("./data/tinyBatch.txt");
     string tmp;
     while (getline(file, tmp)) {
         // Create an entry from the next line and put on the PQ.

ch2/15_MaxPQ/main.cpp

@@ -4,9 +4,14 @@
 
 using namespace std;
 
+/**
+ * Unit tests the {@code MaxPQ} data type.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
     MaxPQ<string> pq;
-    fstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tinyPQ.txt");
+    fstream file("./data/tinyPQ.txt");
     string tmp;
     while (file >> tmp) {
         if (tmp != "-") pq.insert(tmp);

ch2/16_MinPQ/main.cpp

@@ -4,9 +4,14 @@
 
 using namespace std;
 
+/**
+ * Unit tests the {@code MinPQ} data type.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
     MinPQ<string> pq;
-    fstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tinyPQ.txt");
+    fstream file("./data/tinyPQ.txt");
     string tmp;
     while (file >> tmp) {
         if (tmp != "-") pq.insert(tmp);

ch2/18_IndexMaxPQ/main.cpp

@@ -9,7 +9,7 @@ mt19937 g(rd());
 uniform_real_distribution<double> dis(0, 1);
 
 /**
- * Unit tests the {@code IndexMinPQ} data type.
+ * Unit tests the {@code IndexMaxPQ} data type.
  *
  * @param args the command-line arguments
  */

ch2/19_Multiway/main.cpp

@@ -14,9 +14,9 @@ using namespace std;
  * @param args the command-line arguments
  */
 int main() {
-    vector<string> files{"/home/ace/AceDev/C++/algorithm/ch2/data/m1.txt",
-                         "/home/ace/AceDev/C++/algorithm/ch2/data/m2.txt",
-                         "/home/ace/AceDev/C++/algorithm/ch2/data/m1.txt"};
+    vector<string> files{"./data/m1.txt",
+                         "./data/m2.txt",
+                         "./data/m3.txt"};
     vector<fstream> streams;
     for (auto f: files)
         streams.push_back(fstream(f));

ch2/1_Insertion/main.cpp

@@ -4,14 +4,20 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; insertion sorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {
         vec.push_back(tmp);
     }
-  Insertion::sort(vec);
+    Insertion::sort(vec);
 //  Insertion::sort(vec, [](string a, string b) { return a > b; });
     Insertion::show(vec);
 }

ch2/20_Heap/main.cpp

@@ -6,15 +6,13 @@
 using namespace std;
 
 /**
- *  Reads sorted text files specified as command-line arguments;
- *  merges them together into a sorted output; and writes
- *  the results to standard output.
- *  Note: this client does not check that the input files are sorted.
+ * Reads in a sequence of strings from standard input; heapsorts them;
+ * and prints them to standard output in ascending order.
  *
  * @param args the command-line arguments
  */
 int main() {
-    fstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    fstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp)

ch2/2_InsertionX/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; insertion sorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/3_BinaryInsertion/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; insertion sorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/4_Selection/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; selection sorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/5_Shell/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; Shellsorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/6_Merge/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; mergesorts them;
+ * and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/tiny.txt");
+    ifstream file("./data/tiny.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/7_MergeBU/main.cpp

@@ -4,8 +4,14 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; bottom-up
+ * mergesorts them; and prints them to standard output in ascending order.
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/words3.txt");
+    ifstream file("./data/words3.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/8_MergeX/main.cpp

@@ -4,8 +4,15 @@
 
 using namespace std;
 
+/**
+ * Reads in a sequence of strings from standard input; mergesorts them
+ * (using an optimized version of mergesort); 
+ * and prints them to standard output in ascending order. 
+ *
+ * @param args the command-line arguments
+ */
 int main() {
-    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/words3.txt");
+    ifstream file("./data/words3.txt");
     string tmp;
     vector<string> vec;
     while (file >> tmp) {

ch2/9_Inversions/main.cpp

@@ -1,18 +1,16 @@
-// TODO: un-finish
+#include <iostream>
+#include <fstream>
+#include "../head/Inversions.h"
 
-//#include <iostream>
-//#include <fstream>
-//#include "../head/MergeX.h"
-//
-//using namespace std;
-//
-//int main() {
-//    ifstream file("/home/ace/AceDev/C++/algorithm/ch2/data/words3.txt");
-//    string tmp;
-//    vector<string> vec;
-//    while (file >> tmp) {
-//        vec.push_back(tmp);
-//    }
-//    MergeX::sort(vec);
-//    MergeX::show(vec);
-//}
+using namespace std;
+
+/**
+ * Reads a sequence of integers from standard input and
+ * prints the number of inversions to standard output.
+ *
+ * @param args the command-line arguments
+ */
+int main() {
+    vector<int> a{2, 4, 1, 6, 3};
+    cout << Inversions::count(a) << endl;
+}