Title
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.
题目大意：返回仅出现一次的字符位置的索引
这个是CVTE二面让做的哈哈哈哈哈
处女面就是cvte了，结果一面二面终面都过了，这个题就是二面做的，还是挺简单的，一次ac
Solution
//cpp:
class Solution {
public:
int firstUniqChar(string s) {
int nums[256] = { 0 };
for (int i = 0; i < s.length(); i++) {
nums[s[i]]++;
}
for (int i = 0; i < s.length(); i++) {
if (nums[s[i]] == 1)
return i;
}
return -1;
}
};
看discuss，看到了一个pair的新用法
class Solution {
public:
int firstUniqChar(string s) {
unordered_map<char, pair<int, int>> m;
int idx = s.size();
for (int i = 0; i < s.size(); i++) {
m[s[i]].first++;
m[s[i]].second = i;
}
for (auto &p : m) {
if (p.second.first == 1) idx = min(idx, p.second.second);
}
return idx == s.size() ? -1 : idx;
}
};