Time: 52 ms (79.04%), Space: 20.8 MB (24.62%) - LeetHub

Author: JanaSabuj

most-stones-removed-with-same-row-or-column/most-stones-removed-with-same-row-or-column.cpp

@@ -0,0 +1,65 @@
+struct dsu {
+    vector<int> parent;
+    vector<int> sz;
+
+    void _init(int x){
+        parent.assign(x, 0);
+        sz.assign(x,0);
+
+        for (int i = 0; i < x; ++i){
+            parent[i] = i;
+            sz[i] = 1;
+        }
+    }
+
+    int find_set(int x){
+        if(x == parent[x])
+            return x;
+        return parent[x] = find_set(parent[x]);
+    }
+
+    void _union(int a, int b){
+        a = find_set(a);
+        b = find_set(b);
+
+        if(sz[a] < sz[b])
+            swap(a,b);
+
+        parent[b] = a;
+        sz[a] += sz[b];
+    }
+};
+
+class Solution {
+public:
+    int removeStones(vector<vector<int>>& stones) {
+        int n = stones.size();
+        dsu G;
+        G._init(n+1);
+
+        map<int, vector<int>> rowmap, colmap;
+        for (int i = 0; i < n; ++i){
+            rowmap[stones[i][0]].push_back(i);
+            colmap[stones[i][1]].push_back(i);
+        }
+
+        int nodes = n;
+        for (int i = 0; i < n; ++i){
+            for(auto j: rowmap[stones[i][0]]){
+                if(G.find_set(i) != G.find_set(j)){
+                    G._union(i, j);
+                    nodes--;
+                }
+            }
+
+            for(auto j: colmap[stones[i][1]]){
+                if(G.find_set(i) != G.find_set(j)){
+                    G._union(i, j);
+                    nodes--;
+                }
+            }
+        }
+
+        return n - nodes;
+    }
+};