DP min steps stair problem

Dynamic Programming/Minimum_Steps_to_reach_nth_Stair.java

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+package Test_Project;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.*;
+
+
+class Minimum_Steps_to_reach_nth_Stair {
+    public static void main(String[] args) throws java.lang.Exception {
+
+        try {
+            FastReader sc = new FastReader();
+            //Taking input of upto which stair we have to reach
+
+            System.out.println("Enter stair number you want reach : ");
+            int stair_number = sc.nextInt();
+
+            int arr[] = new int[stair_number + 1];
+
+            //Using Top Down Approach of Dynamic Approach
+            int steps = Min_numberOf_Ways(stair_number, arr);
+
+            System.out.println("The Minimum number of steps in which we can reach " + stair_number + "th stair using 1,2,3 steps are = " + steps);
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static int Min_numberOf_Ways(int n, int arr[]) {
+
+        if (n == 0)
+            return 0;
+        if (n == 1 || n == 2 || n == 3)
+            return 1;
+        if (arr[n] == 0) {
+
+            arr[n] = 1+Math.min(Math.min(Min_numberOf_Ways(n - 1, arr), Min_numberOf_Ways(n - 2, arr)), Min_numberOf_Ways(n - 3, arr));
+        }
+        return arr[n];
+    }
+
+
+    static class FastReader {
+        BufferedReader br;
+        StringTokenizer st;
+
+        public FastReader() {
+            br = new BufferedReader(new
+                    InputStreamReader(System.in));
+        }
+
+        String next() {
+            while (st == null || !st.hasMoreElements()) {
+                try {
+                    st = new StringTokenizer(br.readLine());
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+            return st.nextToken();
+        }
+
+        int nextInt() {
+            return Integer.parseInt(next());
+        }
+
+        long nextLong() {
+            return Long.parseLong(next());
+        }
+
+        double nextDouble() {
+            return Double.parseDouble(next());
+        }
+
+        String nextLine() {
+            String str = "";
+            try {
+                str = br.readLine();
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+            return str;
+        }
+    }
+}