int findRadius(vector<int>& houses, vector<int>& heaters) {

sort(heaters.begin(), heaters.end());

int minRadius = 0;

for(int i = 0; i < houses.size(); i++) {

int currRadius = INT_MAX;

auto lbound = lower_bound(heaters.begin(), heaters.end(), houses[i]);

if(lbound != heaters.end()) {

currRadius = *lbound - houses[i];

}

if(lbound != heaters.begin()) {

int prev = *(--lbound);

currRadius = min(currRadius, houses[i] - prev);

}

minRadius = max(minRadius, currRadius);

}

return minRadius;

}