uestc 分割包围（二分）

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 using namespace std;
 5 
 6 const int MAXN = 50010;
 7 int d[MAXN];
 8 int x;
 9 int n, m;
10 
11 int search(int l, int r){
12     int del; //记录消灭的数量
13     int mid;
14     while (r - l>1){
15         mid = (l + r) / 2; //进行二分
16         del = 0;
17         int i = 0;
18         for (int j = i + 1; j<n + 2; j++){
19             if (d[j] - d[i]<mid) //小于mid值就消灭
20                 del++;
21             else  //否则将i值增加，继续查找
22                 i = j;
23         }
24         if (del <= m)//当相等，则说明满足条件，小于则说明值偏小
25             l = mid;
26         else  //大于则折半缩小mid的值
27             r = mid;
28     }
29     return l;
30 }
31 
32 int main(){
33     cin >> x >> n >> m;
34     int ans;
35     int l = x;
36     d[0] = 0; d[n + 1] = x;
37     for (int i = 1; i <= n; i++)
38         cin >> d[i];
39     sort(d, d + n + 2);  //对距离进行排序
40     ans = search(0, x);
41     cout << ans << endl;
42     return 0;
43 }