Create Smallest String With Swaps.java

Author: varunu28

Medium/Smallest String With Swaps.java

@@ -0,0 +1,60 @@
+class Solution {
+  public String smallestStringWithSwaps(String s, List<List<Integer>> pairs) {
+    int n = s.length();
+    DisjointSet disjointSet = new DisjointSet(n);
+    for (List<Integer> pair : pairs) {
+      disjointSet.union(pair.get(0), pair.get(1));
+    }
+    Map<Integer, PriorityQueue<Character>> map = new HashMap<>();
+    for (int i = 0; i < n; i++) {
+      int root = disjointSet.find(i);
+      map.computeIfAbsent(root, k -> new PriorityQueue<>()).offer(s.charAt(i));
+    }
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0; i < s.length(); i++) {
+      sb.append(map.get(disjointSet.find(i)).poll());
+    }
+    return sb.toString();
+  }
+
+  private static final class DisjointSet {
+
+    private final int[] root;
+    private final int[] rank;
+    public int unionCount;
+
+    public DisjointSet(int size) {
+      this.root = new int[size];
+      this.rank = new int[size];
+      for (int i = 0; i < size; i++) {
+        this.root[i] = i;
+        this.rank[i] = 1;
+      }
+      this.unionCount = size;
+    }
+
+    public void union(int nodeOne, int nodeTwo) {
+      int rootOne = find(nodeOne);
+      int rootTwo = find(nodeTwo);
+      if (rootOne != rootTwo) {
+        if (this.rank[rootOne] > this.rank[rootTwo]) {
+          this.root[rootTwo] = rootOne;
+        } else if (this.rank[rootOne] < this.rank[rootTwo]) {
+          this.root[rootOne] = rootTwo;
+        } else {
+          this.root[rootTwo] = rootOne;
+          this.rank[rootOne]++;
+        }
+        this.unionCount--;
+      }
+    }
+
+
+    public int find(int node) {
+      if (node == root[node]) {
+        return node;
+      }
+      return root[node] = find(root[node]);
+    }
+  }
+}