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| class Solution {
public String frequencySort(String s) {
Map<Character, Integer> map = new HashMap<>();
for (int i = 0; i < s.length(); ++i) {
char c = s.charAt(i);
map.merge(c, 1, Integer::sum);
}
List<Character> list = new ArrayList<>(map.keySet());
list.sort((a, b) -> map.get(b) - map.get(a));
StringBuilder builder = new StringBuilder();
for (char c : list) {
builder.append(String.valueOf(c).repeat(map.get(c)));
}
return builder.toString();
}
}
|
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