TCHS-8-500

 

 

Problem Statement
	A common task for math students is to solve 'word math' questions, where each distinct letter represents a distinct digit. Given a list of word math numbers to add, your task is to calculate the greatest possible sum of those numbers. For example, given the expression: TOP + CODER the maximum sum possible by substituting numbers is: 783 + 98654 ------- 99437 with C = 9, D = 6, E = 5, O = 8, P = 3, R = 4 and T = 7. Please note that, for this question, word math numbers are allowed to start with a zero.
Definition
	Class: WordMath Method: maximumSum Parameters: String[] Returns: int Method signature: int maximumSum(String[] summands) (be sure your method is public)
Notes
-	Different letters must represent different digits, identical letters must represent identical digits.
-	Not all digits in the result must appear in the summands.
Constraints
-	summands will contain between 1 and 10 elements, inclusive.
-	Each element of summands will contain between 1 and 8 characters, inclusive.
-	Each element of summands will contain only uppercase letters ('A'-'Z').
-	summands will contain at most 10 distinct letters.
Examples
0)
	{"TOP", "CODER"} Returns: 99437 The example given in the problem statement.
1)
	{"AAA", "AAA"} Returns: 1998 With only one letter, the maximum sum is obtained by setting A = 9.
2)
	{"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"} Returns: 45 Each letter is used once, and there are 10 different letters, so however the digits are distributed this must add up to 0 + 1 + ... + 8 + 9 = 45
3)
	{"AB", "BA"} Returns: 187
4)
	{"READIEST","OPERATIC","TOPCODER","PREDICTS","RAPIDEST","ASTEROID","AIRSPEED"} Returns: 563639653

 

import java.util.Arrays;

public class WordMath {

	int[] weigh = new int[26];

	public int maximumSum(String[] summands) {
		for (String s : summands)
			for (int j = 0, n = s.length(); j < n; j++)
				weigh[s.charAt(j) - 'A'] += Math.pow(10, n - j - 1);
		Arrays.sort(weigh);
		int ret = 0;
		for (int i = 0; i < 10; i++)
			ret += weigh[25 - i] * (9 - i);
		return ret;
	}

}