补第十一周Leetcode 博客

补第十一周Leetcode 博客

389.Find the Difference

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.

分析

S是初始的字符串，T是将S洗牌后额外加了一个字符的新串，我们统计S中26个小写字母各自出现的次数和T中26个小写字母各自出现的次数，对比两次的统计结果，出现不同的那个对应字母就是额外加的一个。

源代码

class Solution {
public:
    char findTheDifference(string s, string t) {
        int alphabet[26];
        int check[26];
        for (int i = 0; i < 26; i++) {
            alphabet[i] = 0;
            check[i] = 0;
        }
        for (int i = 0; i < s.length(); i++) {
            alphabet[s[i] - 'a']++;
        }
        for (int i = 0; i < t.length(); i++) {
            check[t[i] - 'a']++;
        }
        for (int i = 0; i < 26; i++) {
            if (alphabet[i] != check[i]) {
                return i + 'a';
            }
        }
        return 'a';
    }
};

运行结果