Algorithm
Problem Name: 475. Heaters
Winter is coming! During the contest, your first job is to design a standard heater with a fixed warm radius to warm all the houses.
Every house can be warmed, as long as the house is within the heater's warm radius range.
Given the positions of houses and heaters on a horizontal line, return the minimum radius standard of heaters so that those heaters could cover all houses.
Notice that all the heaters follow your radius standard, and the warm radius will the same.
Example 1:
Input: houses = [1,2,3], heaters = [2] Output: 1 Explanation: The only heater was placed in the position 2, and if we use the radius 1 standard, then all the houses can be warmed.
Example 2:
Input: houses = [1,2,3,4], heaters = [1,4] Output: 1 Explanation: The two heater was placed in the position 1 and 4. We need to use radius 1 standard, then all the houses can be warmed.
Example 3:
Input: houses = [1,5], heaters = [2] Output: 3
Constraints:
1 <= houses.length, heaters.length <= 3 * 1041 <= houses[i], heaters[i] <= 109
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
int cmp(const void *a, const void *b) {
return *(int *)a - *(int *)b;
}
int findRadius(int* houses, int housesSize, int* heaters, int heatersSize) {
int r = 0, k;
int i, j;
qsort(houses, housesSize, sizeof(int), cmp);
qsort(heaters, heatersSize, sizeof(int), cmp);
j = 0;
for (i = 0; i < housesSize; i ++) {
while (j < heatersSize - 1 &&
abs(heaters[j + 1] - houses[i]) <= abs(heaters[j] - houses[i])) {
j ++;
}
k = abs(heaters[j] - houses[i]);
if (r < k) r = k;
}
return r;
}
Input
Output
#2 Code Example with Javascript Programming
Code -
Javascript Programming
const findRadius = function(houses, heaters) {
heaters.sort((a, b) => a - b)
return Math.max(...houses.map(h => findMinDistance(h, heaters)))
}
const findMinDistance = (house, heaters) => {
let left = 0
let right = heaters.length - 1
while (left <= right) {
const mid = left + ((right - left) >> 1)
if (heaters[mid] <= house && house <= heaters[mid + 1]) {
return Math.min(house - heaters[mid], heaters[mid + 1] - house)
} else if (heaters[mid] <= house) {
left = mid + 1
} else {
right = mid - 1
}
}
if (left === 0) return heaters[0] - house
if (left === heaters.length) return house - heaters[heaters.length - 1]
}
Input
Output
#3 Code Example with Python Programming
Code -
Python Programming
class Solution:
def findRadius(self, houses, heaters):
heaters.sort()
r = 0
for h in houses:
ind = bisect.bisect_left(heaters, h)
if ind == len(heaters):
r = max(r, h - heaters[-1])
elif ind == 0:
r = max(r, heaters[0] - h)
else:
r = max(r, min(heaters[ind] - h, h - heaters[ind - 1]))
return r
Input
Output
#4 Code Example with C# Programming
Code -
C# Programming
using System;
using System.Linq;
namespace LeetCode
{
public class _0475_Heaters
{
public int FindRadius(int[] houses, int[] heaters)
{
Array.Sort(houses);
Array.Sort(heaters);
var distances = new int[houses.Length];
for (int i = 0; i < houses.Length; i++)
distances[i] = int.MaxValue;
for (int i = 0, h = 0; i < houses.Length && h < heaters.Length;)
{
if (houses[i] <= heaters[h])
{
distances[i] = heaters[h] - houses[i];
i++;
}
else
h++;
}
for (int i = houses.Length - 1, h = heaters.Length - 1; i >= 0 && h >= 0;)
{
if (houses[i] >= heaters[h])
{
distances[i] = Math.Min(distances[i], houses[i] - heaters[h]);
i--;
}
else
h--;
}
return distances.Max();
}
}
}
Input
Output