LeetCode387 First Unique Character in a String


描述

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

样例

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s = "leetcode"
return 0.

s = "loveleetcode",
return 2.

思路

找出在字符串中只出现过一次的字符的下标。

水题…统计一遍即可。

代码

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class Solution {
public:
int firstUniqChar(string s) {
int cnt[26] = {0}, i = 0, ans = -1;
for (char c: s) cnt[c-'a']++;
for (char c: s) {
if (cnt[c-'a'] == 1) {
ans = i;
break;
}
i++;
}
return ans;
}
};