【题解】
二分答案+贪心check.
1 #include<cstdio> 2 #include<algorithm> 3 #include<cstring> 4 #define LL long long 5 #define rg register 6 #define N 200010 7 using namespace std; 8 int n,m,a[N],l,r,mid; 9 inline int read(){ 10 int k=0,f=1; char c=getchar(); 11 while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar(); 12 while('0'<=c&&c<='9')k=k*10+c-'0',c=getchar(); 13 return k*f; 14 } 15 inline bool check(){ 16 int sum=1,last=a[1]; 17 for(rg int i=2;i<=n;i++)if(a[i]-last>=mid){ 18 sum++; 19 last=a[i]; 20 } 21 // printf("mid=%d sum=%d ",mid,sum); 22 return sum>=m; 23 } 24 int main(){ 25 n=read(); m=read(); 26 for(rg int i=1;i<=n;i++) a[i]=read(); 27 sort(a+1,a+1+n); 28 l=0; r=a[n]-a[1]+1; 29 while(l+1<r){ 30 mid=(l+r)>>1; 31 if(check()) l=mid; else r=mid; 32 } 33 printf("%d ",l); 34 return 0; 35 }