Runtime: 209 ms (Top 84.06%) | Memory: 75.6 MB (Top 97.21%)

Author: AnasImloul

scripts/algorithms/R/Rank Transform of a Matrix/Rank Transform of a Matrix.java

@@ -1,10 +1,11 @@
+// Runtime: 209 ms (Top 84.06%) | Memory: 75.6 MB (Top 97.21%)
 class Solution {
     int[] parent;
     public int[][] matrixRankTransform(int[][] matrix) {
         int m = matrix.length;
         int n = matrix[0].length;
         int[][] answer = new int[m][n];
-        
+
         // GROUP BY MATRIX VAL -> {X,Y}
         TreeMap<Integer, List<int[]>> map = new TreeMap<>();
         for(int i = 0; i < m; i++){
@@ -16,97 +17,93 @@ public int[][] matrixRankTransform(int[][] matrix) {
                 map.get(val).add(xy);
             }
         }
-        
-        
+
         // INITIALIZE MIN-RANK ARRAY FOR EVERY COL/ROW
         int[] minX = new int[m];
         int[] minY = new int[n];
-        
+
         for(Integer key : map.keySet()){
             List<int[]> list = map.get(key);
-            
+
             // SPLIT TO GROUPS USING UNION FIND FOR VALs IN SAME COL/ROW
             int lSize = list.size();
             parent = new int[lSize];
             for(int i = 0; i < lSize; i++)
                 parent[i] = i;
-            
+
             // Group the xy by col and row then union by row & by col
             HashMap<Integer, List<Integer>> xMap = new HashMap<>();
             HashMap<Integer, List<Integer>> yMap = new HashMap<>();
             for(int i = 0; i < lSize; i++){
                 int[] xy = list.get(i);
                 int x = xy[0];
                 int y = xy[1];
-                
+
                 if(xMap.get(x) == null)
                     xMap.put(x, new ArrayList<>());
                 if(yMap.get(y) == null)
                     yMap.put(y, new ArrayList<>());
                 xMap.get(x).add(i);
                 yMap.get(y).add(i);
             }
-            
+
             // union by X
             for(Integer xKey : xMap.keySet()){
                 List<Integer> xList = xMap.get(xKey);
                 for(int i = 1; i < xList.size(); i++){
                     union(xList.get(i-1), xList.get(i));
                 }
             }
-            
-            
+
             // union by Y
             for(Integer yKey : yMap.keySet()){
                 List<Integer> yList = yMap.get(yKey);
                 for(int i = 1; i < yList.size(); i++){
                     union(yList.get(i-1), yList.get(i));
                 }
             }
-            
+
             HashMap<Integer, List<int[]>> group = new HashMap<>();
             for(int i = 0; i < lSize; i++){
                 int grp = find(i);
                 if(group.get(grp) == null)
                     group.put(grp, new ArrayList<>());
                 group.get(grp).add(list.get(i));
             }
-            
-            
+
             // SET ANSWER FOR EACH GROUP
             for(Integer grpKey : group.keySet()){
                 int max = 1;
                 List<int[]> sublist = group.get(grpKey);
-                
+
                 // FIND MAX-RANK FOR THIS GROUP
                 for(int[] xy : sublist){
                     int x = xy[0];
                     int y = xy[1];
-                
+
                     max = Math.max(max, Math.max(minX[x], minY[y]));
                 }
-            
+
                 // UPDATE ANSWER = MAX-RANK AND SET NEW MIN-RANK FOR ROW/COL = MAX-RANK+1
                 for(int[] xy : sublist){
                     int x = xy[0];
                     int y = xy[1];
                     answer[x][y] = max;
                     minX[x] = max+1;
                     minY[y] = max+1;
-                }     
+                }
             }
         }
         return answer;
     }
-    
-    
+
     // UNION FIND IMPL
     void union(int a, int b){
         int pa = find(a);
         int pb = find(b);
         parent[pb] = pa;
     }
-    
+
     int find(int a){
         int pa = parent[a];
         if(pa != a){
@@ -115,4 +112,4 @@ int find(int a){
         } else
             return a;
     }
-}
+}