arduino/bluetooth

arduino/bluetooth_arduino.cpp

@@ -0,0 +1,47 @@
+// Basic Bluetooth sketch HC-06_01
+// // Connect the Hc-06 module and communicate using the serial monitor
+// //
+// // The HC-06 defaults to AT mode when first powered on.
+// // The default baud rate is 9600
+// // The Hc-06 requires all AT commands to be in uppercase. NL+CR should not be
+// added to the command string
+// //
+//  
+//   
+//   #include <SoftwareSerial.h>
+//   SoftwareSerial BTserial(2, 3); // RX | TX
+//   // Connect the HC-06 TX to the Arduino RX on pin 2. 
+//   // Connect the HC-06 RX to the Arduino TX on pin 3 through a voltage
+//   divider.
+//   // 
+//    
+//     
+//     void setup() 
+//     {
+//         Serial.begin(9600);
+//             Serial.println("Enter AT commands:");
+//              
+//                  // HC-06 default serial speed is 9600
+//                      BTserial.begin(9600);  
+//                      }
+//                       
+//                       void loop()
+//                       {
+//                        
+//                            // Keep reading from HC-06 and send to Arduino
+//                            Serial Monitor
+//                                if (BTserial.available())
+//                                    {  
+//                                            Serial.write(BTserial.read());
+//                                                }
+//                                                 
+//                                                     // Keep reading from
+//                                                     Arduino Serial Monitor
+//                                                     and send to HC-06
+//                                                         if
+//                                                         (Serial.available())
+//                                                             {
+//                                                                     BTserial.write(Serial.read());
+//                                                                         }
+//                                                                          
+//                                                                          }

arduino/bluetooth_serial_test.py

@@ -0,0 +1,21 @@
+#!/usr/bin/python
+
+#
+#   - Pair bluetooth useing bluetoothctl.
+#       agent on
+#       pair 20:16:02:14:58:51
+#   - Setup serial connection:
+#       sudo rfcomm bind hci0 20:16:02:14:58:51 1
+#
+#   - For module
+#       sudo apt-get install python-serial
+#
+
+import serial
+from time import sleep
+
+bluetoothSerial = serial.Serial( "/dev/rfcomm0", baudrate=9600 )
+
+bluetoothSerial.write( "Test from python." )
+print bluetoothSerial.readline()
+

cpp/stl_rb_tree.cpp

@@ -0,0 +1,43 @@
+/*
+VIM: let b:cf5build="clang -std=c++20 -O2 -pthread -lstdc++ -I. {SRC} -o {OUT}"
+VIM: let b:cf5run="{OUT}"
+*/
+#include <iostream>
+#include <exception>
+#include <chrono>
+#include <set>
+
+int main ( void )
+{try{
+    auto begin = std::chrono::high_resolution_clock::now();
+
+    std::set<int> s({1, 2, 3, 4, 5});
+    //......
+    auto it = s.begin();
+    for (int i = 0; i < 10; i++){
+        std::cout << *it++ << ", " << std::endl;
+    }
+    std::cout << "-------" << std::endl;
+    it = s.end();
+    for (int i = 0; i < 10; i++){
+        std::cout << *it-- << ", " << std::endl;
+    }
+
+    auto end = std::chrono::high_resolution_clock::now();
+    std::chrono::duration<double> seconds = end - begin;
+    std::cout << "Time: " << seconds.count() << std::endl;
+    return 0;
+}
+catch ( const std::exception& e )
+{
+    std::cerr << std::endl
+            << "std::exception(\"" << e.what() << "\")." << std::endl;
+    return 2;
+}
+catch ( ... )
+{
+    std::cerr  << std::endl
+            << "unknown exception." << std::endl;
+    return 1;
+}}
+

puzzles/interviews/training/negabinary.cpp

@@ -0,0 +1,61 @@
+/*
+VIM: let b:lcppflags="-std=c++2a -O2 -pthread -I."
+VIM: let b:wcppflags="/O2 /EHsc /DWIN32"
+VIM-: let b:argv=""
+*/
+#include <iostream>
+#include <exception>
+#include <chrono>
+#include <type_traits>
+#include <iomanip>
+
+
+template <typename T>
+constexpr T negabinary(T v){
+    static_assert(std::is_integral_v<T>, "Only integral types expected.");
+    const T base = -2;
+    const T abs_base = abs(base);
+    std::make_unsigned_t<T> n = 0;
+    int i = 0;
+    while ( v ){
+        T r = v % base;
+        v /= base;
+        if ( r < 0){
+            v +=1;
+            r = abs_base - r;
+        }
+        n |= std::make_unsigned_t<T>(r) << i;
+        ++i;
+    }
+    return n;
+}
+
+
+int main ( void )
+{try{
+    auto begin = std::chrono::high_resolution_clock::now();
+
+
+    for (int i = -16; i < 17; ++i){
+        std::cout << std::setbase(10) << i << " == " << std::setbase(16) << std::showbase << negabinary(i) << std::endl;
+    }
+    //std::cout << negabinary(2.) << std::endl;
+
+    auto end = std::chrono::high_resolution_clock::now();
+    std::chrono::duration<double> seconds = end - begin;
+    std::cout << "Time: " << seconds.count() << std::endl;
+    return 0;
+}
+catch ( const std::exception& e )
+{
+    std::cerr << std::endl
+            << "std::exception(\"" << e.what() << "\")." << std::endl;
+    return 2;
+}
+catch ( ... )
+{
+    std::cerr  << std::endl
+            << "unknown exception." << std::endl;
+    return 1;
+}}
+

puzzles/interviews/training/preorder_tree_construction.cpp.orig

@@ -0,0 +1,102 @@
+/*
+VIM: let b:lcppflags="-std=c++11 -O2 -pthread"
+VIM: let b:wcppflags="/O2 /EHsc /DWIN32"
+VIM: let b:argv=""
+*/
+#include <vector>
+<<<<<<< HEAD
+#include <string>
+||||||| merged common ancestors
+=======
+#include <stack>
+>>>>>>> preorder tree construction: much better algorithm. No need to keep root.
+#include <iostream>
+
+struct node {
+    node * left = nullptr;
+    node * right = nullptr;
+    double data = 0;
+
+    node( double d )
+    : data(d)
+    {}
+};
+
+node * prefix_to_tree( const std::vector<double>& v ){
+
+    if ( !v.size() ){
+        return nullptr;
+    }
+
+    node * root = new node(v[0]);
+
+    std::stack<node*> stack;
+    stack.push(root);
+
+    for ( int i = 1; i < v.size(); ) {
+        if ( v[i] < stack.top()->data ){
+            auto n = new node(v[i++]);
+            stack.top()->left = n;
+            stack.push(n);
+        } else {
+            auto c = stack.top();
+            stack.pop();
+            while( !stack.empty() && stack.top()->data < v[i] ){
+                c = stack.top();
+                stack.pop();
+            }
+
+            auto n = new node(v[i++]);
+            c->right = n;
+            stack.push(n);
+        }
+    }
+
+    return root;
+}
+
+void print( node * root, const std::string& level = "" ){
+    if ( root ) {
+        print( root->left, level + "   ");
+        std::cout << level << "- " << root->data << std::endl;
+        print( root->right, level + "   ");
+    }
+}
+
+void traverse( node * root, std::vector<double>& v ){
+    if ( root ) {
+        v.push_back(root->data);
+        traverse(root->left, v);
+        traverse(root->right, v);
+    }
+}
+
+void test( const std::vector<double>& v ){
+    std::cout << "-----------------------------------------------------" << std::endl;
+    auto r = prefix_to_tree( v );
+    print( r );
+    std::vector<double> w;
+    traverse( r, w );
+    if ( v.size() != w.size() ) {
+        std::cout << "v.size() != w.size() => " << v.size() << " != " << w.size() << std::endl;
+    }
+    for (int i = 0; i < v.size(); ++i ){
+        if (v[i]!=w[i]){
+            std::cout << "error at index " << i << " -> "<< v[i] << " != " << w[i] << std::endl;
+        }
+    }
+}
+
+int main( void ) {
+
+    test( {1} );
+    test( {2, 1, 3} );
+    test( {4, 2, 1, 3, 6, 5, 7} );
+    test( {8, 4, 2, 1, 3, 6, 5, 7, 12, 10, 9, 11, 14, 13, 15} );
+    test( {8, 4, 2,    3, 6, 5, 7, 12, 10, 9, 11, 14, 13, 15} );
+    test( {8, 4,          6, 5, 7, 12, 10, 9,     14, 13, 15} );
+    test( {8,                      12, 10, 9, 11, 14, 13,   } );
+    test( {8, 4, 2, 1,    6,       12, 10,    11, 14,     15} );
+
+    return 0;
+}

puzzles/training/2048.cpp

@@ -15,12 +15,55 @@ void print(const std::vector<int>& row)
     std::cout << std::endl;
 }
 
-void push(std::vector<int> row)
+void print(const std::vector<std::vector<int>>& board)
 {
-    print(row);
-    auto q = row.begin();
-    auto pe = row.end();
-    for (auto p = row.begin()+1; p != pe; ++p){
+    for (const auto& row : board){
+        for (auto i : row){
+            std::cout << i << ',';
+        }
+        std::cout << std::endl;
+    }
+}
+
+struct OneDimVec
+{
+    using board_t = std::vector<int>;
+    using iterator_t = int *;
+    enum {dimentions=1};
+    static iterator_t begin(board_t& b, int n){
+        return b.data();
+    }
+    static iterator_t end(board_t& b, int n){
+        return b.data()+b.size();
+    }
+    static iterator_t next(iterator_t it){
+        return it+1;
+    }
+};
+
+struct OneDimVecReverse
+{
+    using board_t = std::vector<int>;
+    using iterator_t = board_t::reverse_iterator;
+    enum {dimentions=1};
+    static iterator_t begin(board_t& b, int n){
+        return b.rbegin();
+    }
+    static iterator_t end(board_t& b, int n){
+        return b.rend();
+    }
+    static iterator_t next(iterator_t it){
+        return it+1;
+    }
+};
+
+
+template <typename Traits>
+void push(typename Traits::board_t& board, int n)
+{
+    auto q = Traits::begin(board, n);
+    auto pe = Traits::end(board, n);
+    for (auto p = Traits::next(q); p != pe; p=Traits::next(p)){
         if (*p==0){
             continue;
         }
@@ -31,25 +74,154 @@ void push(std::vector<int> row)
         else if (*q == *p){
             *q+=*p;
             *p = 0;
-            ++q;
+            q = Traits::next(q);
         }
         else {
-            *++q = *p;
-            if (*q != *p){
+            q = Traits::next(q);
+            *q = *p;
+            if (q != p){
                 *p = 0;
             }
         }
     }
-    print(row);
 }
 
+template <typename T>
+void test(typename T::board_t v){
+    std::cout << "--------------" << std::endl;
+    print(v);
+    if constexpr (T::dimentions == 1){
+        push<T>(v,0);
+    } else {
+        for (int i = 0; i < T::dim_size(v); ++i){
+            push<T>(v,i);
+        }
+    }
+    std::cout << "-" << std::endl;
+    print(v);
+}
+
+struct BoardTraits
+{
+    using board_t=std::vector<std::vector<int>>;
+    enum {dimentions=2};
+    struct iterator_t {
+        board_t& b;
+        int i;
+        int j;
+        int& operator*(){
+            return b[i][j];
+        }
+        bool operator != (const iterator_t& it){
+            return i != it.i;
+        }
+        iterator_t& operator = (const iterator_t& it){
+            i=it.i;
+            j=it.j;
+            return *this;
+        }
+    };
+};
+
+struct Up : public BoardTraits
+{
+    static int dim_size(const board_t& b){
+        return b[0].size();
+    }
+    static iterator_t begin(board_t& b, int n){
+        return {b, 0, n};
+    }
+    static iterator_t end(board_t& b, int n){
+        return {b, int(b.size()), n};
+    }
+    static iterator_t next(const iterator_t& it){
+        return {it.b, it.i+1, it.j};
+    }
+};
+
+struct Down : public BoardTraits
+{
+    static int dim_size(const board_t& b){
+        return b[0].size();
+    }
+    static iterator_t begin(board_t& b, int n){
+        return {b, int(b.size())-1, n};
+    }
+    static iterator_t end(board_t& b, int n){
+        return {b, -1, n};
+    }
+    static iterator_t next(const iterator_t& it){
+        return {it.b, it.i-1, it.j};
+    }
+};
+
+struct Left : public BoardTraits
+{
+    using iterator_t = std::vector<int>::iterator;
+    static int dim_size(const board_t& b){
+        return b.size();
+    }
+    static iterator_t begin(board_t& b, int n){
+        return b[n].begin();
+    }
+    static iterator_t end(board_t& b, int n){
+        return b[n].end();
+    }
+    static iterator_t next(const iterator_t& it){
+        return it+1;
+    }
+};
+
+struct Right : public BoardTraits
+{
+    using iterator_t = std::vector<int>::reverse_iterator;
+    static int dim_size(const board_t& b){
+        return b.size();
+    }
+    static iterator_t begin(board_t& b, int n){
+        return b[n].rbegin();
+    }
+    static iterator_t end(board_t& b, int n){
+        return b[n].rend();
+    }
+    static iterator_t next(const iterator_t& it){
+        return it+1;
+    }
+};
+
+
 int main ( void )
 {try{
     auto begin = std::chrono::high_resolution_clock::now();
 
-    push({4, 0, 4, 8});
-
+    test<OneDimVec>({4, 0, 4, 8});
+    test<OneDimVecReverse>({4, 0, 4, 8});
+    std::cout << "test" << std::endl;
     //......
+    test<Left>({
+             {4, 0, 4, 8},
+             {2, 0, 2, 8},
+             {1, 1, 0, 0},
+             {4, 0, 4, 4}
+             });
+    test<Right>({
+             {4, 0, 4, 8},
+             {2, 0, 2, 8},
+             {1, 1, 0, 0},
+             {4, 0, 4, 4}
+             });
+    test<Up>({
+             {4, 0, 4, 8},
+             {2, 0, 2, 8},
+             {1, 1, 0, 0},
+             {4, 0, 4, 4}
+             });
+    test<Down>({
+             {4, 0, 4, 8},
+             {2, 0, 2, 8},
+             {1, 1, 0, 0},
+             {4, 0, 4, 4}
+             });
 
     auto end = std::chrono::high_resolution_clock::now();
     std::chrono::duration<double> seconds = end - begin;

puzzles/training/tree_iterator.cpp

@@ -0,0 +1,146 @@
+/*
+VIM: let b:cf5build="clang -std=c++20 -O2 -pthread -lstdc++ -I. {SRC} -o {OUT}"
+VIM: let b:cf5run="{OUT}"
+*/
+#include <iostream>
+#include <exception>
+#include <chrono>
+#include <vector>
+
+struct node {
+    node * parent;
+    node * left;
+    node * right;
+    int val;
+    node(int v, node * p)
+        : parent(p)
+        , left(nullptr)
+        , right(nullptr)
+        , val(v)
+    {}
+};
+
+node * build_tree(const std::vector<int>& t){
+    node * root = nullptr;
+    bool left = true;
+    for (int v : t){
+        if (v!=-1){
+            node * n = new node(v, root);
+            if ( root ){
+                if ( left ){
+                    root->left = n;
+                } else {
+                    root->right = n;
+                }
+            }
+            root = n;
+            left = true;
+        } else {
+            if (!root){
+                break;
+            }
+            if (!left){
+                while ( root->parent && !left){
+                    left = root->parent->left == root;
+                    root = root->parent;
+                }
+                if (!left){
+                    break;
+                }
+            }
+            left = false;
+        }
+    }
+    return root;
+}
+
+void print(const node * root){
+    if ( !root ){
+        std::cout << "-1";
+    } else {
+        std::cout << '(';
+        print(root->left);
+        std::cout << ',' << root->val << ',';
+        print(root->right);
+        std::cout << ')';
+    }
+}
+
+
+class tree_itor {
+    node * n;
+public:
+    tree_itor()
+        : n(nullptr)
+    {}
+    tree_itor(node * _n)
+        : n(leftmost(_n))
+    {}
+
+    tree_itor& operator ++ () {
+        if (n->right){
+            n = leftmost(n->right);
+        } else {
+            while (n->parent && n->parent->right==n){
+                n = n->parent;
+            }
+            if (!n->parent){
+                n = nullptr;
+            } else {
+                n = n->parent;
+            }
+        }
+        return *this;
+    }
+
+    bool operator != (const tree_itor& it) const {
+        return n != it.n;
+    }
+
+    int& operator * (){
+        return n->val;
+    }
+private:
+    node * leftmost(node * n){
+        while ( n->left ){
+            n = n->left;
+        }
+        return n;
+    }
+};
+
+int main ( void )
+{try{
+    auto begin = std::chrono::high_resolution_clock::now();
+
+    std::cout << "------------------------" << std::endl;
+    node * tree = build_tree({1, 2, 3, 4, -1, 5, -1, -1, 6, -1, 7, -1, -1, 8, -1, -1, 4, 10, -1, -1, -1 });
+    print(tree);
+    std::cout << std::endl;
+
+    tree_itor it(tree);
+    tree_itor itEnd;
+    for ( ; it != itEnd; ++it ){
+        std::cout << *it << ", ";
+    }
+    std::cout << std::endl;
+    //......
+
+    auto end = std::chrono::high_resolution_clock::now();
+    std::chrono::duration<double> seconds = end - begin;
+    std::cout << "Time: " << seconds.count() << std::endl;
+    return 0;
+}
+catch ( const std::exception& e )
+{
+    std::cerr << std::endl
+            << "std::exception(\"" << e.what() << "\")." << std::endl;
+    return 2;
+}
+catch ( ... )
+{
+    std::cerr  << std::endl
+            << "unknown exception." << std::endl;
+    return 1;
+}}
+