Merge pull request #97 from rndastech/patch-2

Created solution.cpp

Tasks/task-2-Distant-Friends/solution.cpp

@@ -0,0 +1,103 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define int long long
+class DSU {
+    vector<int> parent, rank;
+public:
+    DSU(int n) {
+        parent.resize(n);
+        rank.resize(n, 0);
+        for (int i = 0; i < n; i++) parent[i] = i;
+    }
+    int find(int x) {
+        if (parent[x] != x) parent[x] = find(parent[x]);
+        return parent[x];
+    }
+    void unite(int x, int y) {
+        int rootX = find(x);
+        int rootY = find(y);
+        if (rootX != rootY) {
+            if (rank[rootX] < rank[rootY]) {
+                parent[rootX] = rootY;
+            } else if (rank[rootX] > rank[rootY]) {
+                parent[rootY] = rootX;
+            } else {
+                parent[rootY] = rootX;
+                rank[rootX]++;
+            }
+        }
+    }
+};
+signed main() {
+     ios_base::sync_with_stdio(false); 
+     cin.tie(NULL);
+     cout.tie(NULL);
+     int t=1;
+     while(t--){
+    int N, K, R;
+    cin >> N >> K >> R;
+    vector<pair<pair<int, int>, pair<int, int>>> drs(R);
+    for (int i = 0; i < R; i++) {
+        int r, c, r_, c_;
+        cin >> r >> c >> r_ >> c_;
+        drs[i] = {{r, c}, {r_, c_}};
+    }
+    vector<pair<int, int>> fd(K);
+    for (int i = 0; i < K; i++) {
+        int r, c;
+        cin >> r >> c;
+        fd[i] = {r, c};
+    }
+    int tot = N * N;
+    DSU dsu(tot);
+    set<pair<pair<int, int>, pair<int, int>>> ds;
+    for (auto &i : drs) {
+        int r1 = i.first.first - 1, c1 = i.first.second - 1;
+        int r2 = i.second.first - 1, c2 = i.second.second - 1;
+        ds.insert({{r1, c1}, {r2, c2}});
+        ds.insert({{r2, c2}, {r1, c1}});
+    }
+    for (int r = 0; r < N; r++) {
+        for (int c = 0; c < N; c++) {
+            if (c + 1 < N) {
+                int nr = r, nc = c + 1;
+                if (ds.find({{r, c}, {nr, nc}}) == ds.end()) {
+                    dsu.unite(r * N + c, nr * N + nc);
+                 }
+                }
+            if (r + 1 < N) {
+                int nr = r + 1, nc = c;
+                if (ds.find({{r, c}, {nr, nc}}) == ds.end()) {
+                    dsu.unite(r * N + c, nr * N + nc);
+                 }
+                }
+             if (c - 1 >= 0) {
+                int nr = r, nc = c - 1;
+                if (ds.find({{r, c}, {nr, nc}}) == ds.end()) {
+                    dsu.unite(r * N + c, nr * N + nc);
+                 }
+                }
+            if (r - 1 >= 0) {
+                int nr = r - 1, nc = c;
+                if (ds.find({{r, c}, {nr, nc}}) == ds.end()) {
+                    dsu.unite(r * N + c, nr * N + nc);
+                 }
+                }
+        }
+    }
+    map<int, int> m;
+    for (auto &i : fd) {
+        int r = i.first - 1;
+        int c = i.second - 1;
+        int tem = dsu.find(r*N + c);
+        m[tem]++;
+    }
+    int KK = K * (K - 1) / 2;
+    int ans = 0;
+    for (auto &i : m) {
+        ans += i.second * (i.second - 1) / 2;
+    }
+    cout<< KK - ans<<endl;
+     }
+    return 0;
+}