1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 using namespace std; 6 int c[50005],tr,tl,f[30][50005],a[50005],s,n,k; 7 void del(int x) 8 { 9 while (x<=n) 10 { 11 c[x]-=1; 12 x+=(x&(-x)); 13 } 14 } 15 void add(int x) 16 { 17 while (x<=n) 18 { 19 c[x]+=1; 20 x+=(x&(-x)); 21 } 22 } 23 int query(int x) 24 { 25 int sum=0; 26 while (x) 27 { 28 sum+=c[x]; 29 x-=(x&(-x)); 30 } 31 return sum; 32 } 33 int get(int l,int r) 34 { 35 while (tl<l) 36 { 37 del(a[tl]); 38 s-=query(a[tl]); 39 tl++; 40 } 41 while (tl>l) 42 { 43 tl--; 44 s+=query(a[tl]); 45 add(a[tl]); 46 } 47 while (tr<r) 48 { 49 tr++; 50 s+=tr-tl-query(a[tr]); 51 add(a[tr]); 52 } 53 while (tr>r) 54 { 55 del(a[tr]); 56 s-=tr-tl-query(a[tr]); 57 tr--; 58 } 59 return s; 60 } 61 void solve(int x,int l,int r,int L,int R) 62 {int i,Mid; 63 if (l>r) return; 64 int mid=(l+r)/2; 65 Mid=mid; 66 for (i=L;i<=min(mid-1,R);i++) 67 { 68 int t=f[x-1][i]+get(i+1,mid); 69 if (f[x][mid]>=t) 70 { 71 f[x][mid]=t; 72 Mid=i; 73 } 74 } 75 solve(x,l,mid-1,L,Mid); 76 solve(x,mid+1,r,Mid,R); 77 } 78 int main() 79 {int i,j; 80 scanf("%d%d",&n,&k); 81 for (i=1;i<=n;i++) 82 scanf("%d",&a[i]); 83 memset(f,127/2,sizeof(f)); 84 tl=1;tr=0; 85 for (i=1;i<=n;i++) 86 { 87 f[1][i]=get(1,i); 88 } 89 for (i=2;i<=k;i++) 90 { 91 solve(i,i,n,i-1,n); 92 } 93 printf("%d",f[k][n]); 94 }