diff --git a/cpp/prevoi19_robots.cpp b/cpp/prevoi19_robots.cpp
index c26ad4d..0be62e0 100644
--- a/cpp/prevoi19_robots.cpp
+++ b/cpp/prevoi19_robots.cpp
@@ -1,5 +1,6 @@
 #include <iostream>
 #include <vector>
+#include <algorithm>
 #include <climits>
 using namespace std;
 
@@ -7,9 +8,6 @@ typedef long long ll;
 
 struct Point {
     ll x, y;
-
-    Point(ll x = 0, ll y = 0) : x(x), y(y) {
-    }
 };
 
 ll manhattan(const Point &a, const Point &b) {
@@ -24,55 +22,46 @@ bool isPossible(ll D, const vector<Point> &chargers, const Point &start, ll N) {
     ll min_v = v0 - N;
     ll max_v = v0 + N;
 
-    vector<Point> test_points;
-
-    vector<ll> u_candidates = {min_u, max_u};
-    vector<ll> v_candidates = {min_v, max_v};
+    vector<ll> u_candidates = {min_u, max_u, u0};
+    vector<ll> v_candidates = {min_v, max_v, v0};
 
     for (const Point &c: chargers) {
         ll cu = c.x + c.y;
         ll cv = c.x - c.y;
-
         u_candidates.push_back(cu - D);
         u_candidates.push_back(cu + D);
         v_candidates.push_back(cv - D);
         v_candidates.push_back(cv + D);
     }
 
-    u_candidates.push_back(u0);
-    v_candidates.push_back(v0);
+    sort(u_candidates.begin(), u_candidates.end());
+    u_candidates.erase(unique(u_candidates.begin(), u_candidates.end()), u_candidates.end());
+
+    sort(v_candidates.begin(), v_candidates.end());
+    v_candidates.erase(unique(v_candidates.begin(), v_candidates.end()), v_candidates.end());
 
     for (ll u: u_candidates) {
         for (ll v: v_candidates) {
-            if ((u + v) % 2 == 0) {
-                ll x = (u + v) / 2;
-                ll y = (u - v) / 2;
-                test_points.push_back(Point(x, y));
-            } else {
-                ll x1 = (u + v) / 2;
-                ll y1 = (u - v) / 2;
-                test_points.push_back(Point(x1, y1));
+            if (u < min_u || u > max_u || v < min_v || v > max_v) continue;
 
-                ll x2 = (u + v + 1) / 2;
-                ll y2 = (u - v - 1) / 2;
-                test_points.push_back(Point(x2, y2));
+            ll x = (u + v) / 2;
+            ll y = (u - v) / 2;
+
+            if ((u + v) % 2 != 0) continue;
+
+            Point p = {x, y};
+            if (manhattan(p, start) > N) continue;
+
+            bool valid = true;
+            for (const Point &c: chargers) {
+                if (manhattan(p, c) < D) {
+                    valid = false;
+                    break;
+                }
             }
+            if (valid) return true;
         }
     }
-
-    for (const Point &p: test_points) {
-        if (manhattan(p, start) > N) continue;
-
-        bool valid = true;
-        for (const Point &c: chargers) {
-            if (manhattan(p, c) < D) {
-                valid = false;
-                break;
-            }
-        }
-        if (valid) return true;
-    }
-
     return false;
 }
 
@@ -97,7 +86,6 @@ int main() {
 
     while (left <= right) {
         ll mid = left + (right - left) / 2;
-
         if (isPossible(mid, chargers, start, N)) {
             left = mid + 1;
         } else {