Return the number of unique ways you can climb the staircase












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There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.



For example, if N is 4, then there are 5 unique ways:



1, 1, 1, 1
2, 1, 1
1, 2, 1
1, 1, 2
2, 2


What if, instead of being able to climb 1 or 2 steps at a time, you could climb any number from a set of positive integers X? For example, if X = {1, 3, 5}, you could climb 1, 3, or 5 steps at a time.



public class DailyCodingProblem12 {
public static void main(String args) {
int X = { 1, 2 };
int N = 4;
int result = solution(N, X);
System.out.println(result);

int X1 = { 1, 2, 3 };
N = 4;
result = solution(N, X1);
System.out.println(result);

int X2 = { 1, 2, 3 };
N = 3;
result = solution(N, X2);
System.out.println(result);
}

static int solution(int N, int X) {
int memory = new int[N + 1];
memory[0] = 1;
memory[1] = 1;
return noOfWays(N, X, memory);
}

static int noOfWays(int N, int X, int memory) {
if (memory[N] != 0) {
return memory[N];
}
int noOfWays = 0;
for (int i = 0; i < X.length && (N - X[i] >= 0); i++) {
memory[N - X[i]] = noOfWays(N - X[i], X, memory);
noOfWays += memory[N - X[i]];
}
return noOfWays;

}


}



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    0












    $begingroup$


    There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.



    For example, if N is 4, then there are 5 unique ways:



    1, 1, 1, 1
    2, 1, 1
    1, 2, 1
    1, 1, 2
    2, 2


    What if, instead of being able to climb 1 or 2 steps at a time, you could climb any number from a set of positive integers X? For example, if X = {1, 3, 5}, you could climb 1, 3, or 5 steps at a time.



    public class DailyCodingProblem12 {
    public static void main(String args) {
    int X = { 1, 2 };
    int N = 4;
    int result = solution(N, X);
    System.out.println(result);

    int X1 = { 1, 2, 3 };
    N = 4;
    result = solution(N, X1);
    System.out.println(result);

    int X2 = { 1, 2, 3 };
    N = 3;
    result = solution(N, X2);
    System.out.println(result);
    }

    static int solution(int N, int X) {
    int memory = new int[N + 1];
    memory[0] = 1;
    memory[1] = 1;
    return noOfWays(N, X, memory);
    }

    static int noOfWays(int N, int X, int memory) {
    if (memory[N] != 0) {
    return memory[N];
    }
    int noOfWays = 0;
    for (int i = 0; i < X.length && (N - X[i] >= 0); i++) {
    memory[N - X[i]] = noOfWays(N - X[i], X, memory);
    noOfWays += memory[N - X[i]];
    }
    return noOfWays;

    }


    }



    How do I improve my solution? There is a way to save more space?









    share









    $endgroup$















      0












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      0





      $begingroup$


      There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.



      For example, if N is 4, then there are 5 unique ways:



      1, 1, 1, 1
      2, 1, 1
      1, 2, 1
      1, 1, 2
      2, 2


      What if, instead of being able to climb 1 or 2 steps at a time, you could climb any number from a set of positive integers X? For example, if X = {1, 3, 5}, you could climb 1, 3, or 5 steps at a time.



      public class DailyCodingProblem12 {
      public static void main(String args) {
      int X = { 1, 2 };
      int N = 4;
      int result = solution(N, X);
      System.out.println(result);

      int X1 = { 1, 2, 3 };
      N = 4;
      result = solution(N, X1);
      System.out.println(result);

      int X2 = { 1, 2, 3 };
      N = 3;
      result = solution(N, X2);
      System.out.println(result);
      }

      static int solution(int N, int X) {
      int memory = new int[N + 1];
      memory[0] = 1;
      memory[1] = 1;
      return noOfWays(N, X, memory);
      }

      static int noOfWays(int N, int X, int memory) {
      if (memory[N] != 0) {
      return memory[N];
      }
      int noOfWays = 0;
      for (int i = 0; i < X.length && (N - X[i] >= 0); i++) {
      memory[N - X[i]] = noOfWays(N - X[i], X, memory);
      noOfWays += memory[N - X[i]];
      }
      return noOfWays;

      }


      }



      How do I improve my solution? There is a way to save more space?









      share









      $endgroup$




      There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.



      For example, if N is 4, then there are 5 unique ways:



      1, 1, 1, 1
      2, 1, 1
      1, 2, 1
      1, 1, 2
      2, 2


      What if, instead of being able to climb 1 or 2 steps at a time, you could climb any number from a set of positive integers X? For example, if X = {1, 3, 5}, you could climb 1, 3, or 5 steps at a time.



      public class DailyCodingProblem12 {
      public static void main(String args) {
      int X = { 1, 2 };
      int N = 4;
      int result = solution(N, X);
      System.out.println(result);

      int X1 = { 1, 2, 3 };
      N = 4;
      result = solution(N, X1);
      System.out.println(result);

      int X2 = { 1, 2, 3 };
      N = 3;
      result = solution(N, X2);
      System.out.println(result);
      }

      static int solution(int N, int X) {
      int memory = new int[N + 1];
      memory[0] = 1;
      memory[1] = 1;
      return noOfWays(N, X, memory);
      }

      static int noOfWays(int N, int X, int memory) {
      if (memory[N] != 0) {
      return memory[N];
      }
      int noOfWays = 0;
      for (int i = 0; i < X.length && (N - X[i] >= 0); i++) {
      memory[N - X[i]] = noOfWays(N - X[i], X, memory);
      noOfWays += memory[N - X[i]];
      }
      return noOfWays;

      }


      }



      How do I improve my solution? There is a way to save more space?







      java programming-challenge





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