318. Maximum Product of Word Lengths - cocoder39/coco39_LC GitHub Wiki
318. Maximum Product of Word Lengths
an interesting idea here is transforming string to 26-bit int, so we can use & operation from int to check if there is intersection between two strings.
O(n^2)
int maxProduct(vector<string>& words) {
int res = 0;
int sz = words.size();
vector<int> mask(sz);
for (int i = 0; i < sz; i++) {
for (char c : words[i])
mask[i] |= 1 << (c - 'a'); //transform word to 26-bit int, ignoring repeated char
for (int j = 0; j < i; j++) {
if ((mask[i] & mask[j]) == 0)
res = max(res, (int)words[i].length() * (int)words[j].length());
}
}
return res;
}