Merge pull request #63 from Ankur-Dwivedi22/med_day9

chore: completed medium day 9 task author : Ankur-Dwivedi22

Medium/Day9/Solution.cpp

@@ -1 +1,41 @@
 // Write your code here
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long ll;
+constexpr int MAX_NODES = 1000005; // Maximum number of nodes + 5
+constexpr int PRIME_MODULUS = 1000000007; // A prime number used for modulo operation
+
+int totalNodes, color, nodeValues[MAX_NODES], parentTags[MAX_NODES]; // nodeValues: stores the color of each node, parentTags: stores the number of times the parent node has been visited
+ll product = 1; // product: the final answer
+vector<int> childrenLists[MAX_NODES]; // childrenLists: stores the list of children for each node
+
+void traverse(int node, int parent) {
+    if (nodeValues[node] <= 0) { // If the node has a non-positive color value, the product becomes 0
+        product = 0;
+        return;
+    }
+    parentTags[parent]++; // Increment the parent node's tag
+    product = (product * nodeValues[node]) % PRIME_MODULUS; // Update the product
+    for (int child : childrenLists[node]) { // Traverse through the children of the current node
+        if (child != parent) {
+            nodeValues[child] -= parentTags[node] + 1; // Decrease the child node's color value by the parent node's tag + 1
+            parentTags[child]++; // Increment the child node's tag
+            traverse(child, node); // Recursively traverse the child node
+        }
+    }
+}
+
+int main() {
+    cin >> totalNodes >> color;
+    for (int i = 1; i <= totalNodes; i++) {
+        nodeValues[i] = color; // Initialize the color values for all nodes
+    }
+    for (int i = 1, parent, child; i < totalNodes; i++) {
+        scanf("%d%d", &parent, &child);
+        childrenLists[parent].push_back(child); // Add the child node to the parent node's children list
+        childrenLists[child].push_back(parent); // Add the parent node to the child node's children list
+    }
+    traverse(1, 0); // Start traversing from the root node (node 1)
+    printf("%lld\n", product); // Print the final answer
+    return 0;
+}