Adding medium/hard puzzles & challenges...

puzzles/medium/teads-sponsored-contest.cpp

@@ -0,0 +1,74 @@
+// https://www.codingame.com/ide/puzzle/teads-sponsored-contest
+// Xavier Morel - 2016-03-17
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <map>
+#include <set>
+#include <utility>
+#include <cmath>
+
+using namespace std;
+map<int, vector<int>> points;
+
+int findFarthestNode(int origin, int *distanceOut)
+{
+    int maxDistance = 0;
+    int farthestNode = 0;
+    vector<pair<int,int>> process;
+
+    set<int> discovered;
+
+    process.push_back(pair<int,int>(origin,0));
+    while (process.size() > 0) {
+        pair<int,int> node = process.back(); // node, distance
+        process.pop_back();
+        discovered.insert(node.first);
+
+        if (node.second > maxDistance) {
+            maxDistance = node.second;
+            farthestNode = node.first;
+        }
+
+        for (int adjNode : points[node.first]) {
+            if (discovered.find(adjNode) == discovered.end()) {
+                process.push_back(pair<int,int>(adjNode, node.second + 1));
+            }
+        }
+
+    }
+
+    if (distanceOut != 0) {
+        *distanceOut = maxDistance;
+    }
+
+    return farthestNode;
+}
+
+
+
+int main()
+{
+    int n;
+    cin >> n; cin.ignore();
+    int firstNode;
+    for (int i = 0; i < n; i++) {
+        int xi;
+        int yi;
+        cin >> xi >> yi; cin.ignore();
+        points[xi].push_back(yi);
+        points[yi].push_back(xi);
+        if (i == 0) {
+            firstNode = xi;
+        }
+    }
+
+    int distance;
+    int farNode = findFarthestNode(firstNode, &distance);
+    cerr << "Farthest node from origin is " << farNode << " with distance of " << distance << endl;
+    farNode = findFarthestNode(farNode, &distance);
+    cerr << "Farthest node from previous is " << farNode << " with distance of " << distance << endl;
+
+    cout << ceil(distance / 2.0f) << endl;
+}