g2701_2800.s2707_extra_characters_in_a_string.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g2701_2800.s2707_extra_characters_in_a_string;

// #Medium #Array #String #Hash_Table #Dynamic_Programming #Trie
// #2023_09_15_Time_37_ms_(74.40%)_Space_44.2_MB_(74.60%)

import java.util.Arrays;

public class Solution {
    public int minExtraChar(String s, String[] dictionary) {
        return tabulationApproach(s, dictionary);
    }

    private int tabulationApproach(String s, String[] dictionary) {
        int m = s.length();
        int[] dp = new int[m + 1];
        for (int i = m - 1; i >= 0; i--) {
            dp[i] = dp[i + 1] + 1;
            int finalI = i;
            Arrays.stream(dictionary)
                    .filter(word -> s.startsWith(word, finalI))
                    .mapToInt(String::length)
                    .map(n -> dp[finalI + n])
                    .forEach(prev -> dp[finalI] = Math.min(dp[finalI], prev));
        }
        return dp[0];
    }
}