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Offer50.java
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Offer50.java
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package com.yore.offer;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* @author jia bing wen
* @date 2021/5/28 15:30
* @description
*/
public class Offer50 {
public char firstUniqChar(String s) {
Set<Character> repeat = new HashSet<>();
Set<Character> once = new HashSet<>();
for (int i = 0; i < s.length(); i++) {
if (repeat.contains(s.charAt(i))) {
continue;
}
if (once.contains(s.charAt(i))) {
repeat.add(s.charAt(i));
once.remove(s.charAt(i));
} else {
once.add(s.charAt(i));
}
}
for (int i = 0; i < s.length(); i++) {
if (once.contains(s.charAt(i))) {
return s.charAt(i);
}
}
return ' ';
}
public char firstUniqChar1(String s) {
Map<Character, Integer> map = new HashMap<>();
for (int i = 0; i < s.length(); i++) {
char ch = s.charAt(i);
map.put(ch, map.getOrDefault(ch, 0) + 1);
}
for (int i = 0; i < s.length(); i++) {
if (map.get(s.charAt(i)) == 1) {
return s.charAt(i);
}
}
return ' ';
}
}