2048(C++)

#include <iostream>
#include <vector>
#include <algorithm>
#include <stdlib.h>
#include <iomanip>
using namespace std;

int rand(int i){
  return rand()%i;
}

class Board{
 
  public:
    Board(const int size){
      
      dim=1<<size;
      grid.resize(dim,vector<int>(dim,-1));
      
      int p1 = rand(1);
      grid[p1/dim][p1%dim]=2;
      int p2 = rand(5);
      grid[p2/dim][p2%dim]=2;
    }
  
    void push(const char dir){
      
      switch(dir){
        case 'j': // left
          for(auto i=0u;i<dim;i++){
            grid[i]=push_helper(grid[i]);
          }
          break;
        case 'l': // right
          for(auto i=0u;i<dim;i++){
            vector<int> v;
            for(auto j=dim-1;j>=0;j--){
              v.push_back(grid[i][j]);
            }
            grid[i]=push_helper(v);
            std::reverse(grid[i].begin(),grid[i].end());
          }
          break;
        case 'k': // down
          for(auto i=0u;i<dim;i++){
            vector<int> v;
            for(auto j=dim-1;j>=0;j--){
              v.push_back(grid[j][i]);
            }
            auto res=push_helper(v);
            for(auto j=dim-1;j>=0;j--){ 
              grid[j][i]=res[dim-1-j];
            }
          }
          break;
        case 'i': // up
          for(auto i=0u;i<dim;i++){
            vector<int> v;
            for(auto j=0u;j<dim;j++){
              v.push_back(grid[j][i]);
            }
            auto res=push_helper(v);
            for(auto j=0;j<dim;j++){
              grid[j][i]=res[j];
            }
          }
          break;
        default:
          break;
      }
      fill_new();
    }
    
    void print(){
      for(auto i=0u;i<dim;i++){
        for(auto j=0u;j<dim;j++){
          cout << setw(3) <<  grid[i][j] << " ";
        }
        cout << "\n";
      }
    }
  
    bool is_lost(){  
      for(auto move:{'j','l','i','k'})
      {  
        Board b = *this;
        b.push(move);
        for(auto i=0u;i<dim;i++){
          for(auto j=0u;j<dim;j++){
            if(b.at(i,j)!=grid[i][j]){
              return false;
            }
          }
        }
      }
      return true; 
    }
  
    int at(int i,int j){
      return grid[i][j];
    }
  
  private:
    int dim;
    vector< vector<int> > grid;
  
    vector<int> push_helper(vector<int>& v){
      vector<int> res;
      
      bool mergable = true;
      for(auto i=0u;i<v.size();i++){
        if(v[i]!=-1){
          if(mergable and !res.empty() and res.back()==v[i]){
            res[res.size()-1]*=2;
            mergable=false;
          }else{
            res.push_back(v[i]);
            mergable=true;
          }
        }
      }
      res.resize(dim,-1);
      return res;
    }
  
    vector<pair<int,int>> empty_locs(){ 
      vector<pair<int,int>> v;
      for(auto i=0u;i<dim;i++){
        for(auto j=0u;j<dim;j++){
          if(grid[i][j]==-1){
            v.push_back(make_pair(i,j));
          }
        }
      } 
      return v;
    }
    
    void fill_new(){
      auto r=empty_locs();
      if(r.empty()){
        return;
      }

      int val = 1<<(1+rand(2));
      int p = rand(r.size());
      // cout << val << " " << r[p].first << " " << r[p].second << "\n";
      grid[ r[p].first][r[p].second]=val;

    }
  
};

int main() {
  
  int size=2;
  cin >> size ;
  Board b(size); // 4
  b.print();
  while(true){
    char type;
    cin >> type;
    b.push(type);
    b.print();
    cout << "---------------------------------------\n";
    if(b.is_lost()){
      std::cout << "Game Over\n";
      break;
    }
  }
  
  return 0;
}