318. Maximum Product of Word Lengths
阿新 • • 發佈:2021-07-31
package LeetCode_318 import java.util.* /** * 318. Maximum Product of Word Lengths * https://leetcode.com/problems/maximum-product-of-word-lengths/ * Given a string array words, return the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. * If no such two words exist, return 0. Example 1: Input: words = ["abcw","baz","foo","bar","xtfn","abcdef"] Output: 16 Explanation: The two words can be "abcw", "xtfn". Example 2: Input: words = ["a","ab","abc","d","cd","bcd","abcd"] Output: 4 Explanation: The two words can be "ab", "cd". Example 3: Input: words = ["a","aa","aaa","aaaa"] Output: 0 Explanation: No such pair of words. Constraints: 1. 2 <= words.length <= 1000 2. 1 <= words[i].length <= 1000 3. words[i] consists only of lowercase English letters. **/ class Solution { /** * solution: use IntArray to store each word's mask of char, then compare by AND; * Time complexity:O(n^2), Space complexity:O(n) * */ fun maxProduct(words: Array<String>): Int { if (words.isEmpty()) { return 0 } val size= words.size val marks = IntArray(size) for (i in 0 until size) { for (c in words[i]) { /* *creating unique number for each string, * marks[i] is a 32 bit Int where 0 bit corresponds to 'a', 1 bit corresponds 'b' and so on, * for example 'abcw' is: 10000000000000000000111 **/ marks[i] = marks[i] or (1 shl (c - 'a')) } } var max = 0 for (i in 0 until size) { for (j in i + 1 until size) { //is two string NOT contains same character when we do AND the result will be ZERO if (marks[i] and marks[j] == 0) { max = Math.max(max, words[i].length * words[j].length) } } } return max } }