questions:
https://www.codewars.com/kata/566fc12495810954b1000030/train/java
https://www.codewars.com/kata/58f5c63f1e26ecda7e000029/train/java
https://www.codewars.com/kata/51b6249c4612257ac0000005/train/typescript
https://www.codewars.com/kata/586c0909c1923fdb89002031/train/typescript

# Connect 4

export class Connect4 {

   private game: Number[][];  // 7 columns and 6 rows
   private player : Number;   // 1: player 1 , 2: player 2
   private hasWinner : boolean;   
   
   constructor() { 
        this.game = [];
        this.player = 1
        this.hasWinner = false
        for(var i: number = 0; i < 6; i++) {
            this.game[i] = [];
            for(var j: number = 0; j< 7; j++) {
                this.game[i][j] = 0;
            }
        }
   }
 
   play(col: number): string{
    // 1. check if game is already finishd
    if(this.hasWinner){
      return "Game has finished!"
    }
    // 2. check if the given col is full
    if(this.game[0][col] != 0){
      return "Column full!"
    }

     // 3 placing 
     let level = 5
     while(this.game[level][col] != 0){
       level-=1
     }
     if(this.game[level][col] === 0){
       this.game[level][col]  = this.player
     }else{
       return "internal error"
     }

     // debug
     this.print()

    // 4. check if this move will make a winner
    if(this.checkWinner(col)){
       this.hasWinner = true
       if(this.player === 1){
         return "Player 1 wins!"
       }else{
         return "Player 2 wins!"
       }
    }

    // 5. switch player and tell whos turn
     let whosTurn = ""
     if(this.player === 1){
       whosTurn =  "Player 1 has a turn"
       this.player = 2
     }else{
      whosTurn =  "Player 2 has a turn"
      this.player=1 
     }
     return whosTurn
   }

   print(){
    console.log("\n")
    for(let i=0;i<this.game.length;i++){
      let str = ""
      for(let j=0;j<this.game[0].length;j++){
        str += String(this.game[i][j])
      }
      console.log(str,"\n")
    }
   }

    //  00 01 02 03 04 05 06
    //  10 11 12 13 14 15 16
    //  20 21 22 23 24 25 26
    //  30 31 32 33 34 35 36
    //  40 41 42 43 44 45 46
    //  50 51 52 53 54 55 56

   checkWinner(col:number):boolean{
     // 1. check vertically
     for(let i=0;i<this.game.length;i++){
       let row = (this.game[i])
       if(this.exceeded4continues(row)){
         return true
       }
     }

     // 2. check herozontally
     let subarray
     for(let i = 0; i < this.game[0].length; i++){
        subarray = [] 
        for(let j = 0; j < this.game.length; j++){
          subarray.push(this.game[j][i]);    
        }
        if(this.exceeded4continues((subarray))){
          return true
        }
      }
      
      // 3. check diagonally
      for( let k = 0 ; k <= 7 + 6 - 2; k++ ) {
        subarray =[]
        for( let j = 0 ; j <= k ; j++ ) {
          let i = k - j;
            if( i < 6 && j < 7 ) {
              subarray.push(this.game[i][j]); 
            }
        }
        if(this.exceeded4continues(subarray)){
          return true
        }
    }
     return false
   }

   exceeded4continues(subarray:Array<any>):boolean{
     let player_1 =0
     let max = 0
     for(let i=0;i<subarray.length;i++){
        if(subarray[i] == 1){
          player_1 +=1
          max = Math.max(max,player_1)
        }else{
          player_1=0
        }
     }
     if(max>=4){
       return true
     }
     let player_2 =0
     max =0
     for(let i=0;i<subarray.length;i++){
      if(subarray[i] == 2){
        player_2 +=1
        max = Math.max(max,player_2)
      }else{
        player_2=0
      }
   }
    if(max>=4){
     return true
   }
     return false
   }
 }

# Roman Numerals Decoder

export function solution(roman: string): number {
  let dict = new Map();
  dict.set("I",1)
  dict.set("V",5)
  dict.set("X",10)
  dict.set("L",50)
  dict.set("C",100)
  dict.set("D",500)
  dict.set("M",1000)
  dict.set(undefined,0)
  let charArray = Array.from(roman);
  let total = dict.get(charArray[charArray.length-1]);
  for(let i=0;i<charArray.length;i++){
    let key_1 = charArray[i]
    let key_2 = charArray[i-1]
    if(dict.get(key_2)>=dict.get(key_1)){
       total+= dict.get(key_2)
    }else{
       total-= dict.get(key_2)
    }
  }
  return total
}

# Mexican Wave

import java.util.ArrayList;
public class MexicanWave {

    public static String[] wave(String str) {
        ArrayList<String> list = new ArrayList<String>();
        for(int i=0;i<str.length();i++){
          char char_1 = str.charAt(i);
          if(char_1 != ' '){
           char char_2 = Character.toUpperCase(char_1);
           list.add(str.substring(0,i)+char_2+str.substring(i+1)); 
          }
        }
//         for(String s:list){
//           System.out.println(s);
//         }

        return list.toArray(new String[0]);
    }
    
}

# Count the Digit

public class CountDig {
    
    public static int nbDig(int n, int d) {
        int count = 0;
        int target = String.valueOf(d).charAt(0);
        for(int i=0;i<=n;i++){
          String str = String.valueOf(i*i);
          char [] charArray = str.toCharArray();
          for(int j=0;j<charArray.length;j++){
            if(charArray[j] == target){
              count++;
            }
          }
        }
        return count;
    }
}