389. Find the Difference(easy)

Easy

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Given two strings s and t which consist of only lowercase letters.

String t is generated by random shuffling string s and then add one more letter at a random position.

Find the letter that was added in t.

Example:

Input:

s = "abcd"

t = "abcde"

 

Output:

e

 

Explanation:

'e' is the letter that was added.

 

C++：

/*
 * @Autor: SourDumplings
 * @Date: 2019-09-20 08:35:52
 * @Link: https://github.com/SourDumplings/
 * @Email: changzheng300@foxmail.com
 * @Description: https://leetcode.com/problems/find-the-difference/
 */

class Solution
{
public:
    char findTheDifference(string s, string t)
    {
        int hashTable[26];
        fill(hashTable, hashTable + 26, 0);
        for (auto &&c : s)
        {
            ++hashTable[c - 'a'];
        }
        for (auto &&c : t)
        {
            int i = c - 'a';
            if (hashTable[i] == 0)
            {
                return c;
            }
            else
            {
                --hashTable[i];
            }
        }
        return -1;
    }
};

 Java：

import java.util.Arrays;

/*
 * @Autor: SourDumplings
 * @Date: 2019-09-20 08:45:12
 * @Link: https://github.com/SourDumplings/
 * @Email: changzheng300@foxmail.com
 * @Description: https://leetcode.com/problems/find-the-difference/
 */

class Solution
{
    public char findTheDifference(String s, String t)
    {
        int[] hashTable = new int[26];
        int ls = s.length();
        int lt = t.length();
        Arrays.fill(hashTable, 0);
        for (int i = 0; i < ls; i++)
        {
            char c = s.charAt(i);
            ++hashTable[c - 'a'];
        }
        for (int i = 0; i < lt; i++)
        {
            char c = t.charAt(i);
            int j = c - 'a';
            if (hashTable[j] == 0)
            {
                return c;
            }
            else
            {
                --hashTable[j];
            }
        }
        return ' ';
    }
}