CareerCup

package com.cracking.olap_vision;

public class DecodeString {
	
	public static void main(String[] args) {
		System.out.printf("String = %s , Value = %d\n","A",Decode("A"));
		
		System.out.printf("String = %s , Value = %d\n","AA",Decode("AA"));
		System.out.printf("String = %s , Value = %d\n","AZ",Decode("AZ"));
		
		System.out.printf("String = %s , Value = %d\n","BA",Decode("BA"));
		System.out.printf("String = %s , Value = %d\n","BZ",Decode("BZ"));
		
		System.out.printf("String = %s , Value = %d\n","CA",Decode("CA"));
		System.out.printf("String = %s , Value = %d\n","AAA",Decode("AAA"));
		System.out.printf("String = %s , Value = %d\n","AAZ",Decode("AAZ"));
		
		System.out.printf("String = %s , Value = %d\n","ABA",Decode("ABA"));
		System.out.printf("String = %s , Value = %d\n","ABZ",Decode("ABZ"));
	}
	
	public static int Decode(String str) {
		
		final int interval = 26;
		char[] arr = str.toCharArray();
		int len = arr.length;
		int sum = 0;
		
		for(int posInterval=0, i=len-1; i>=0; i--,posInterval++) {
			char ch = arr[i];
			int value = (ch - 'A') +1;
			value *= Math.pow(interval, posInterval);
			sum += value;
		}
		return sum;
	}

}

Output:
String = A , Value = 1
String = AA , Value = 27
String = AZ , Value = 52
String = BA , Value = 53
String = BZ , Value = 78
String = CA , Value = 79
String = AAA , Value = 703
String = AAZ , Value = 728
String = ABA , Value = 729
String = ABZ , Value = 754

Known problem, and here is the solution.
[ codereview.stackexchange.com/questions/44545/excel-column-string-to-row-number-and-vice-versa ]

Using simple number system it can be done .
BA -> 26x2+1 =53
BC ->26x2+3 =55
BCC-> 26^2x2+26^1x3+26^0x3

public static void main(String[] args){
  	calc("BAC");
  }
 
  public static void calc(String str){
  	int n = str.length()-1;
    char[] carr = str.toCharArray();
    
    int sum = carr[n] - 'A' +1;
    n--;
    int i = 1;
    while(n >= 0){
 		sum += (carr[n] - 'A' + 1)*(int)Math.pow(26, i);
      	n--;
      	i++;
    }
    System.out.println(sum);
  }

JS

function getValue(str) {

	var sum = 0;

	for (var i = 0; i < str.length; i++) {
  
  	var c = str.charAt(i);
    
    if (c >= 'A' && c <= 'Z') {
    	sum += Math.pow(26, str.length - i - 1) * (c.charCodeAt(0) - "A".charCodeAt(0) + 1)
    } else {
    	console.error("Invalid input!");
    }
  }
	
  return sum;
}

int Decode(string const &s)
{
	int val = 1;
	int n = 0;
	for (int i = s.size() - 1; i >= 0; --i) {
		n += val * (s[i] - 'A' + 1);
		val *= 26;
	}
	return n;
}

def findValue(s):
    v=0
    for c in s:
        v = 26* v+ 1 +ord (c) - ord ('A')
    return v

class BaseAlphabet {
    final List ALPHABET = 'A'..'Z'
    final Map MAP = ALPHABET.withIndex(1).collectEntries { k, v -> [(k): v] }
    
    int getBase10(String s) {
        s.toUpperCase().findAll { it }
            .collect { MAP[it] }
            .inject(0) { acc, val -> acc * 26 + val}
    }
}

Map tests = [
    'A': 1,
    'B': 2,
    'Z': 26,
    'AA': 27,
    'AB': 28,
    'AZ': 52,
    'BA': 53,
    'CC': 81,
    'cafe': 53565,
]
def ba = new BaseAlphabet()
tests.collect { k, v ->
    def actual = ba.getBase10(k)
    println "getBase10(${k}) = ${actual} \t(${actual == v})"
    actual == v
}.any { !it }

getBase10(A) = 1 (true)
getBase10(B) = 2 (true)
getBase10(Z) = 26 (true)
getBase10(AA) = 27 (true)
getBase10(AB) = 28 (true)
getBase10(AZ) = 52 (true)
getBase10(BA) = 53 (true)
getBase10(CC) = 81 (true)
getBase10(cafe) = 53565 (true)

def findValue(s):
    v = 0

    b = range(len(s))
    b.reverse()

    c = zip(s,b)

    for char, val in c:
        f = ord(char) - ord('A') + 1
        v = 26 ** val * f + v

    return v

t_l = {"A": 1, "AZ": 52, "CA": 79, "AAZ": 728, "ABZ": 754}


for k,v in t_l.items():
    print ("{}: {}".format(k, v))
    assert(findValue(k) == v)

hi

Function in C

#include <stdio.h>
#include <string.h>

long stringtonum(char* str)
{
	int i=strlen(str)-1;
	long sum=0, mul = 1;

	while(i >= 0)
	{
		sum += mul*(1+str[i]-'A');
		i--; mul *= 26;
	}

	return sum;
}

<?php
$input = 'AAAA';
$inputArray = str_split($input);
$length = count($inputArray);
$result = 0;

foreach ($inputArray as $key => $val) {
    $pow = $length - ($key + 1);
    $result += pow(26, $pow) * getNumber($val);
}

echo "The result is " . $result;

function getNumber($char) {
    return ord($char) - 64;
}

<?php
$input = 'AAAA';
$inputArray = str_split($input);
$length = count($inputArray);
$result = 0;

foreach ($inputArray as $key => $val) {
    $pow = $length - ($key + 1);
    $result += pow(26, $pow) * getNumber($val);
}

echo "The result is " . $result;

function getNumber($char) {
    return ord($char) - 64;
}

<?php
$input = 'AAAA';
$inputArray = str_split($input);
$length = count($inputArray);
$result = 0;

foreach ($inputArray as $key => $val) {
    $pow = $length - ($key + 1);
    $result += pow(26, $pow) * getNumber($val);
}

echo "The result is " . $result;

function getNumber($char) {
    return ord($char) - 64;

}

def findValue(s):
v=0
for p,x in enumerate(reversed(s)):
v+=26**p*(ord(x)-ord('A')+1)
return v