英文:
Find Duplicate character in a String
问题
public static String duplicate(String str) {
HashMap<Character, Integer> map = new HashMap<Character, Integer>();
for(int i = 0; i < str.length(); i++) {
if(map.containsKey(str.charAt(i))) {
return String.valueOf(str.charAt(i));
}
map.put(str.charAt(i), i);
}
return "-1";
}
英文:
I want to return a duplicated char in a string or "-1" if not found.
The problem is my compiler asks me to change the return type to char at this line return str.charAt(i); but I dont want to use char return type, I want to use String as return type. Can you help me please?
public static String duplicate(String str) {
HashMap<Character, Integer> map = new HashMap<Character, Integer>();
for(int i=0; i<str.length(); i++) {
if(map.containsKey(str.charAt(i))) {
return str.charAt(i);
}
map.put(str.charAt(i), i);
}
return "-1";
}
答案1
得分: 0
使用 Character.toString()
public static String duplicate(String str) {
HashMap<Character, Integer> map = new HashMap<Character, Integer>();
for(int i=0; i<str.length(); i++) {
if(map.containsKey(str.charAt(i))) {
return Character.toString(str.charAt(i));
}
map.put(str.charAt(i), i);
}
return "-1";
}
英文:
Use Character.toString()
public static String duplicate(String str) {
HashMap<Character, Integer> map = new HashMap<Character, Integer>();
for(int i=0; i<str.length(); i++) {
if(map.containsKey(str.charAt(i))) {
return Character.toString(str.charAt(i));
}
map.put(str.charAt(i), i);
}
return "-1";
}
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