求教 区间DP怎么写？

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
using namespace std;
int n,k,f[150][150],t;
struct lala
{
    int high,a;
}nn[150];
int min(int aa,int bb){if (aa<bb) return aa;return bb;}
bool cmp(lala a1,lala b1) {return a1.high<b1.high;}
int main()
{
    scanf("%d%d",&n,&k); memset(f,0x3f,sizeof f);
    for (int i=1;i<=n;i++) scanf("%d%d",&nn[i].high,&nn[i].a); 
    f[1][0]=0; sort(nn+1,nn+n+1,cmp);
    for (int i=2;i<=n;i++)
     f[i][0]=f[i-1][0]+abs(nn[i].a-nn[i-1].a);
    //printf("%d\n",f[4][0]);
    for (int i=1;i<=n;i++) f[0][i]=0;
    for (int num=1;num<=k;num++)
     for (int i=n;i>=1;i--)         //前i个 
      for (int j=1;j<i;j++)        //删掉第j个 
      {    
       if (j<num) continue;
       f[i][num]=min(f[i][num],f[j-1][num-1]+f[i][0]-f[j+1][0]+abs(nn[j-1].a-nn[j+1].a));
      } 
    printf("%d",f[n][k]);
return 0;
}