Runtime2 msBeats88.7%
Memory40.4 MBBeats99.43%

#N1061. Lexicographically Smallest Equivalent String
problem link
#solution

class Solution {
    public String smallestEquivalentString(String s1, String s2, String base) {
        int[] graph = new int[26];
        for(int i=0; i<26; i++) graph[i]=i;
        for(int i=0; i<s1.length(); i++){
            int a1=s1.charAt(i)-'a';
            int a2=s2.charAt(i)-'a';
            int p1=find(graph, a1);
            int p2=find(graph, a2);
            if(p1<p2) graph[p2]=p1;
            else graph[p1]=p2;
        }
        StringBuilder sb = new StringBuilder();
        for(Character ch: base.toCharArray())
            sb.append((char)(find(graph, ch-'a')+'a'));
        return sb.toString();
    }
    public int find(int[] graph, int x){
        while(x!=graph[x])
            x=graph[x];
        return x;
    }
}