g1101_1200.s1177_can_make_palindrome_from_substring.Solution Maven / Gradle / Ivy

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package g1101_1200.s1177_can_make_palindrome_from_substring;

// #Medium #String #Hash_Table #Bit_Manipulation #Prefix_Sum
// #2022_03_03_Time_13_ms_(93.08%)_Space_136.3_MB_(53.08%)

import java.util.ArrayList;
import java.util.List;

/**
 * 1177 - Can Make Palindrome from Substring\.
 *
 * Medium
 *
 * You are given a string `s` and array `queries` where queries[i] = [left_i, right_i, k_i]. We may rearrange the substring s[left_i...right_i] for each query and then choose up to k_i of them to replace with any lowercase English letter.
 *
 * If the substring is possible to be a palindrome string after the operations above, the result of the query is `true`. Otherwise, the result is `false`.
 *
 * Return a boolean array `answer` where `answer[i]` is the result of the i^th query `queries[i]`.
 *
 * Note that each letter is counted individually for replacement, so if, for example s[left_i...right_i] = "aaa", and k_i = 2, we can only replace two of the letters. Also, note that no query modifies the initial string `s`.
 *
 * **Example :**
 *
 * **Input:** s = "abcda", queries = \[\[3,3,0],[1,2,0],[0,3,1],[0,3,2],[0,4,1]]
 *
 * **Output:** [true,false,false,true,true]
 *
 * **Explanation:** 
 *
 * queries[0]: substring = "d", is palidrome. 
 *
 * queries[1]: substring = "bc", is not palidrome. 
 *
 * queries[2]: substring = "abcd", is not palidrome after replacing only 1 character. q
 *
 * ueries[3]: substring = "abcd", could be changed to "abba" which is palidrome. Also this can be changed to "baab" first rearrange it "bacd" then replace "cd" with "ab". 
 *
 * queries[4]: substring = "abcda", could be changed to "abcba" which is palidrome.
 *
 * **Example 2:**
 *
 * **Input:** s = "lyb", queries = \[\[0,1,0],[2,2,1]]
 *
 * **Output:** [false,true]
 *
 * **Constraints:**
 *
 * *   1 <= s.length, queries.length <= 10⁵
 * *   0 <= left_i <= right_i < s.length
 * *   0 <= k_i <= s.length
 * *   `s` consists of lowercase English letters.
**/
public class Solution {
    public List canMakePaliQueries(String s, int[][] queries) {
        return this.canMakeP(s, queries);
    }

    private List canMakeP(String s, int[][] qs) {
        int n = s.length();
        int[] counts = new int[n];
        for (int i = 0; i < n; i++) {
            int m = 0;
            if (i > 0) {
                m = counts[i - 1];
            }
            char c = s.charAt(i);
            m = m ^ (1 << (c - 'a'));
            counts[i] = m;
        }
        List ans = new ArrayList<>();
        for (int[] q : qs) {
            ans.add(check(q, counts));
        }
        return ans;
    }

    private boolean check(int[] q, int[] counts) {
        int l = q[0];
        int r = q[1];
        int k = q[2];
        int prev = l > 0 ? counts[l - 1] : 0;
        int kk = Integer.bitCount(prev ^ counts[r]);
        return (kk / 2) <= k;
    }
}