题目
https://leetcode-cn.com/problems/di-yi-ge-zhi-chu-xian-yi-ci-de-zi-fu-lcof
解法
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| public class SO50_firstUniqChar {
public static void main(String[] args) {
}
public char firstUniqChar(String s) {
if (s== null || s.length() ==0) return ' ';
Map<Character, Boolean> map = new HashMap<>();
char[] str = s.toCharArray();
for (char c : str) {
map.put(c, !map.containsKey(c));
}
for (char c : str) {
if (map.get(c)) return c;
}
return ' ';
}
public char firstUniqChar2(String s) {
if (s== null || s.length() ==0) return ' ';
Map<Character, Boolean> map = new LinkedHashMap<>();
char[] strs = s.toCharArray();
for (char c : strs) {
map.put(c, !map.containsKey(c));
}
for (Map.Entry<Character, Boolean> d : map.entrySet()) {
if (d.getValue()) return d.getKey();
}
return ' ';
}
public char firstUniqChar1(String s) {
int[] count = new int[26];
for(int i = 0;i<s.length();i++){
count[s.charAt(i)-'a']++;
}
for(int i = 0;i<s.length();i++){
if(count[s.charAt(i)-'a']==1) return s.charAt(i);
}
return ' ';
}
}
|
