POJ_2456_Agressive_cows

 1 #include<cstdio>
 2 #include<algorithm>
 3 using std :: sort;
 4 
 5 const int maxn=100005;
 6 int n,c;
 7 int a[maxn];
 8 
 9 void init()
10 {
11     scanf("%d%d",&n,&c);
12     for(int i=1;i<=n;i++) scanf("%d",&a[i]);
13     sort(a+1,a+n+1);
14 }
15 
16 bool judge(int x)
17 {
18     int last=1;
19     for(int i=2;i<=c;i++)
20     {
21         int now=last+1;
22         while(now<=n&&(a[now]-a[last]<x)) now++;
23         if(now>n) return false;
24         last=now;
25     }
26     return true;
27 }
28 
29 
30 int bsearch(int x,int y)
31 {
32     while(x<y)
33     {
34         int m=x+(y-x+1)/2;
35         if(judge(m)) x=m;
36         else y=m-1;
37     }
38     return x;
39 }
40 
41 void solve()
42 {
43     int INF=(a[n]-a[1])/(c-1);
44     printf("%d\n",bsearch(1,INF));
45 }
46 
47 int main()
48 {
49     freopen("cow.in","r",stdin);
50     freopen("cow.out","w",stdout);
51     init();
52     solve();
53     fclose(stdin);
54     fclose(stdout);
55     return 0;
56 }