pipioj 1208: 选球问题（简单贪心）

http://www.pipioj.online/problem.php?id=1208

#define IO std::ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define bug(x) cout<<#x<<" is "<<x<<endl
#include <bits/stdc++.h>
#define iter ::iterator
using namespace  std;
typedef long long ll;
typedef pair<int,ll>P;
#define pb push_back
#define mk make_pair
#define se second
#define fi first
#define rs o*2+1
#define ls o*2
const ll mod=1e9+7;
const int N=1e2+5;
int T,n,k;
char s[N];
int a[N];
int main(){
    //IO;
    while(~scanf("%d%d",&n,&k)){
        scanf("%s",s+1);
        for(int i=1;i<=n;i++)a[i]=s[i]-'a'+1;
        sort(a+1,a+1+n);
        int ans=a[1],pre=a[1],cnt=1;
        for(int i=2;i<=n;i++){
            if(cnt==k)break;
            if(a[i]>=pre+2){
                ans+=a[i];
                cnt++;
                pre=a[i];
            }
        }
        if(cnt!=k)ans=-1;
        printf("%d
",ans);

    }
}