1+ // Runtime: 164 ms
2+ // Memory Usage: 27.8 MB
3+ class Solution {
4+ public:
5+ 6+ void _union (int x, int y, vector<int >&parent, vector<int >&rank) {
7+ int xp = find (x, parent);
8+ int yp = find (y, parent);
9+ 10+ // path compression
11+ if (rank[xp] > rank[yp]) {
12+ parent[yp] = xp;
13+ } else {
14+ parent[xp] = yp;
15+ }
16+ 17+ if (rank[x] == rank[y]) {
18+ rank[y]++;
19+ }
20+ }
21+ 22+ int find (int x, vector<int >&parent) {
23+ if (parent[x] != x) {
24+ parent[x] = find (parent[x], parent);
25+ }
26+ return parent[x];
27+ }
28+ 29+ int minMalwareSpread (vector<vector<int >>& graph, vector<int >& initial) {
30+ int n = graph.size ();
31+ vector<int > parent (n);
32+ vector<int > rank (n, 1 );
33+ for (int i = 0 ; i < n; i++) {
34+ parent[i] = i;
35+ }
36+ 37+ for (int i = 0 ; i < n; i++) {
38+ for (int j = i + 1 ; j < n; j++) {
39+ if (graph[i][j]) _union (i, j, parent, rank);
40+ }
41+ }
42+ 43+ vector<int > malware (n, 0 );
44+ vector<int > areaOfEveryParent (n, 0 );
45+ 46+ for (int i = 0 ; i < n; i++) {
47+ areaOfEveryParent[find (i, parent)]++;
48+ }
49+ 50+ int index = INT_MAX;
51+ for (int a : initial) {
52+ malware[find (a, parent)]++;
53+ index = min (index, a);
54+ }
55+ 56+ int mx = 1 ;
57+ 58+ for (int i : initial) {
59+ int f = find (i, parent);
60+ if (malware[f] == 1 ) {
61+ if (mx < areaOfEveryParent[f]) {
62+ mx = areaOfEveryParent[f];
63+ index = i;
64+ }
65+ else if (mx == areaOfEveryParent[f]) {
66+ index = min (index, i);
67+ }
68+ }
69+ }
70+ 71+ return index;
72+ }
73+ };
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