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algorithm notes: leetcode#389 find the difference

admin 11月 12, 2020 0

Problem

Solution

Analysis

Python implementation

class :
    def findTheDifference(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: str
        """
        counter_s = dict()
        for c in s:
            counter_s[c] = counter_s.get(c, 0) + 1
        for c in t:
            if not counter_s.get(c, 0):
                return c
            counter_s[c] -= 1

Java implementation

class  {
    public char findTheDifference(String s, String t) {
        Map<Character, Integer> counter = new HashMap<>();
        
        for(char c : s.toCharArray())
            counter.put(c, counter.getOrDefault(c, 0) + 1);
        for(char c : t.toCharArray()){
            if(counter.getOrDefault(c, 0) == 0)
                return c;
            counter.put(c, counter.get(c) - 1);
        }
        return 0;
    }
}

Time complexity

O(n).

Space complexity

O(n).

Link

389. Find the Difference
(中文版) 算法笔记: 力扣#389 找不同