在第8组数据上WA了一天，后来才发现问题；
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 200009
#define inf 1e15
using namespace std;
int n,k,q;
struct node
{
int score;
int pain;
bool operator<(const node &t)const
{
return pain<t.pain;
}
} no[maxn]; bool cmp(const node &a,const node &b)
{
return a.score>b.score;
} bool vis[maxn];
int s[maxn]; long long check(int p)
{
long long ans=;
int cnt_1=;
for(int i=;i<=n;i++)
if(no[i].score>=p-)cnt_1++;
cnt_1-=k-;
int cnt_2=;
for(int i=;i<=n&&cnt_2<cnt_1;i++)
{
if(no[i].score==p||no[i].score==(p-))
{
ans+=no[i].pain;
cnt_2++;
vis[i]=;
}
}
for(int i=;i<=n&&cnt_2<p;i++)
{
if(!vis[i])
{
ans+=no[i].pain;
cnt_2++;
}
}
memset(vis,,sizeof vis);
return ans;
} int main()
{
scanf("%d%d",&n,&k);
for(int i=; i<=n; i++)
scanf("%d%d",&no[i].score,&no[i].pain);
sort(no+,no+n+,cmp);
int tar=no[k].score;
sort(no+,no+n+);
long long ans=inf;
for(int i=tar;i<=tar+;i++)
{
if(i>n)break;
ans=min(ans,check(i));
}
if(ans==inf)ans=-;
cout<<ans<<endl;;
}