Skip to main content


 A message containing letters from A-Z is being encoded to numbers using the following mapping:

'A' -> 1
'B' -> 2
'Z' -> 26

Given a non-empty string containing only digits, determine the total number of ways to decode it.

Example 1:

Input: "12"
Output: 2
Explanation: It could be decoded as "AB" (1 2) or "L" (12).

Example 2:

Input: "226"
Output: 3
Explanation: It could be decoded as "BZ" (2 26), "VF" (22 6), or "BBF" (2 2 6).
class Solution {
    public int numDecodings(String s) {
        int ways=0;
        return ways;
    int countDecoding(char[] digits, int n){

       // System.out.println(" digits "+disgits[0]);
              // for base condition "01123" should return 0    
                 // base cases 
    if (n == 0 || (n == 1 && digits[0]!='0')) 
       return 1; 
    if (digits[0]=='0')   { 
         return 0; 

     // Initialize count 
    int count = 0;  
    // If the last digit is not 0, then  
    // last digit must add to 
    // the number of words 
    if(digits[n - 1] > '0') 
    count = countDecoding(digits, n - 1); 
     // If the last two digits form a number 
    // smaller than or equal to 26, 
    // then consider last two digits and recur 
    if (digits[n - 2] == '1' || (digits[n - 2] == '2' && digits[n - 1] < '7')) 
    count += countDecoding(digits, n - 2); 
    return count; 



Popular posts from this blog

Heap implementation in JAVA

In this tutorial we will see all the functionalities of heaps implemented through java language.

package com.problems.heap;publicclassHeapFunctions{//Function to generate maxheapify where root is max than childspublicvoidmaxHeapify(int Arr[],int i,int N){int largest;int left =2*i+1;//left childint right =2*i +2;//right child System.out.println("left"+" "+left); System.out.println("right"+" "+right); System.out.println("Max size"+" "+N);if(left< N && Arr[left]> Arr[i]){ largest = left; System.out.println("largest left"+largest);}else{ largest = i; System.out.println("largest i"+largest);}if(right < N && Arr[right]> Arr[largest]){ largest = right; System.out.println("largest right"+largest);}if(largest != i ){ System.out.println("No largest"+largest); Arr=swap (A…

Solved: The index 1 is out of range.

This error usually comes when we try to insert data in a query where there is no index defined for it.
Example :-
String strQuery=“select * from location where city_id=? ”;
The question mark will be the the first index if we want to insert data so if we call a function like-
oPreparedStatement = oConnection.prepareStatement(strQuery);
here we are sending 235 as a first parameter so it will work fine but as soon as we write something after it like
then it will throw “The index 2 is out of range” since there is no place to send this value in a query hence it will throw the same error. Here index defines the parameter for which there is no place in the query.
To rectify this we need to write query like-
String strQuery=“select * from location where city_id=? And city_name=? ”;
then it will work fine.
The cases in which these errors can occur is-
1)Query is coming out as null. 2)No of parameters are more than the parameters p…