tyvj1097 mm不哭

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
using namespace std;
struct MM{
    int d;
    int w;
};
int n,v;
long long lf[1005][1005],rf[1005][1005],sumw[1005];
MM mm[1005];
bool cmp(MM a,MM b){
    return a.d < b.d;
}
int main(){
    cin>>n>>v;
    for(int i = 1;i <= n;i++){
        scanf("%d%d",&mm[i].d,&mm[i].w);
    }
    sort(mm+1,mm+1+n,cmp);
    for(int i = 0;i <= n;i++){
        for(int j = 0;j <= n;j++){
            lf[i][j] = rf[i][j] = 1087654321;
        }
    }
    for(int i = 1;i <= n;i++) sumw[i] = sumw[i-1] + mm[i].w;
    lf[v][v] = rf[v][v] = 0;
    for(int l = 1;l <= n - 1;l++){
        for(int i = max(v - l,1);i <= v;i++){
            int j = i + l;
            if(j > n) continue;
            lf[i][j] = min(lf[i+1][j] + (mm[i+1].d - mm[i].d) * (sumw[i] + sumw[n] - sumw[j]),rf[i+1][j] + (mm[j].d - mm[i].d) * (sumw[i] + sumw[n] - sumw[j]));
            rf[i][j] = min(rf[i][j-1] + (mm[j].d - mm[j-1].d) * (sumw[i-1] + sumw[n] - sumw[j-1]),lf[i][j-1] + (mm[j].d - mm[i].d) *(sumw[i-1] + sumw[n] - sumw[j-1]));
        }
    }
    cout<<(lf[1][n] < rf[1][n] ? lf[1][n] : rf[1][n]);
    return 0;
}