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| class Solution {
static Map<Integer, Integer> map = new HashMap<>();
int n;
int ans = Integer.MIN_VALUE;
int[] hash;
private int get(int cur) {
if (map.containsKey(cur)) return map.get(cur);
int ans = 0;
for (int i = cur; i > 0; i -= lowbit(i)) ans++;
map.put(cur, ans);
return ans;
}
private int lowbit(int x) {
return x & -x;
}
public int maxLength(List<String> arr) {
n = arr.size();
Set<Integer> set = new HashSet<>();
for (String s : arr) {
int val = 0;
for (char c : s.toCharArray()) {
int t = c - 'a';
if (((val >> t) & 1) != 0) {
val = -1;
break;
}
val |= (1 << t);
}
if (val != -1) set.add(val);
}
n = set.size();
if (n == 0) return 0;
hash = new int[n];
int idx = 0, total = 0;
for (int i : set) {
hash[idx++] = i;
total |= i;
}
dfs(0, 0, total);
return ans;
}
private void dfs(int u, int cur, int total) {
if (get(cur | total) <= ans) return;
if (u == n) {
ans = Math.max(ans, get(cur));
return;
}
if ((hash[u] & cur) == 0) {
dfs(u + 1, hash[u] | cur, total - (total & hash[u]));
}
dfs(u + 1, cur, total);
}
}
|
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