leecode第四百七十五题（供暖器）

class Solution {
public:
    int findRadius(vector<int>& houses, vector<int>& heaters) {
        int res=0;
        int len1=houses.size();
        int len2=heaters.size();
        sort(houses.begin(),houses.end());//先排序
        sort(heaters.begin(),heaters.end());
        int index_sta=0;
        int index_end=len2-1;
        for(int i=0;i<len1/2;i++)//对于第一个房屋和最后一个房屋，检测各自前后两个供暖器
        {
            while(index_sta<len2-1&&houses[i]-heaters[index_sta+1]>0)
                index_sta++;
            while(index_end>0&&houses[len1-1-i]-heaters[index_end-1]<0)
                index_end--;
            
            int temp1;//取前后供暖器位置最近的
            if(index_sta==len2-1)
                temp1=abs(houses[i]-heaters[index_sta]);
            else
                temp1=min(abs(houses[i]-heaters[index_sta]),abs(houses[i]-heaters[index_sta+1]));
            
            int temp2;
            if(index_end==0)
                temp2=abs(houses[len1-1-i]-heaters[index_end]);
            else
                temp2=min(abs(houses[len1-1-i]-heaters[index_end]),abs(houses[len1-1-i]-heaters[index_end-1]));
            
            if(max(temp1,temp2)>res)//取两个位置里最大的
                res=max(temp1,temp2);
        }
        
        return res;
    }
};