Create optimize-water-distribution-in-a-village.cpp

Author: kamyu104

C++/optimize-water-distribution-in-a-village.cpp

@@ -0,0 +1,61 @@
+// Time:  O(nlogn)
+// Space: O(n)
+
+class Solution {
+public:
+    int minCostToSupplyWater(int n, vector<int>& wells, vector<vector<int>>& pipes) {
+        vector<tuple<int, int, int>> nodes;
+        for (int i = 0; i < wells.size(); ++i) {
+            nodes.emplace_back(wells[i], 0, i + 1);
+        }
+        for (int i = 0; i < pipes.size(); ++i) {
+            nodes.emplace_back(pipes[i][2], pipes[i][0], pipes[i][1]);
+        }
+        sort(nodes.begin(), nodes.end());
+        int result = 0;
+        UnionFind union_find(n + 1);
+        for (const auto& [c, x, y] : nodes) {
+            if (!union_find.union_set(x, y)) {
+                continue;
+            }
+            result += c;
+            if (union_find.count() == 1) {
+                break;
+            }
+        }
+        return result;
+    }
+
+private:
+    class UnionFind {
+    public:
+        UnionFind(const int n) : set_(n), count_(n) {
+            iota(set_.begin(), set_.end(), 0);
+        }
+
+        int find_set(const int x) {
+           if (set_[x] != x) {
+               set_[x] = find_set(set_[x]);  // Path compression.
+           }
+           return set_[x];
+        }
+
+        bool union_set(const int x, const int y) {
+            int x_root = find_set(x), y_root = find_set(y);
+            if (x_root == y_root) {
+                return false;
+            }
+            set_[min(x_root, y_root)] = max(x_root, y_root);
+            --count_;
+            return true;
+        }
+        
+        int count() const {
+            return count_;
+        }
+
+    private:
+        vector<int> set_;
+        int count_;
+    };
+};