[LeetCode] 387. First Unique Character in a String (C++)

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[LeetCode] 387. First Unique Character in a String (C++)

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Given a string, find the first non-repeating character in it and return it’s index. If it doesn’t exist, return -1.

Examples:

s = “leetcode”
return 0.

s = “loveleetcode”,
return 2.

Note: You may assume the string contain only lowercase letters.

class Solution {
public:
    int firstUniqChar(string s) {
        /*
        Record the number of occurrences of each character
        */
        map<char,int> occurence;
        for(char c:s) {
            occurence[c]++;
        }
        for(int j=0;j<s.size();j++) {
            if(occurence[s.at(j)]==1) {
                return j;
            }
        }
        return -1;
    }
};


/*
Submission Detail:

Runtime: 76 ms, faster than 28.63% of C++ online submissions for First Unique Character in a String.
Memory Usage: 13 MB, less than 98.32% of C++ online submissions for First Unique Character in a String.

*/