codeforces 999C Alphabetic Removals

​​http://www.elijahqi.win/archives/3819​​​
先统计再贪心

最后暴力模拟

#include<bits/stdc++.h>
using namespace std;
const int N=4e5+10;
char s[N],s1[N];int n,k,top,cnt[50];
int main(){
//  freopen("c.in","r",stdin);
    scanf("%d%d",&n,&k);scanf("%s",s+1);
    for (int i=1;i<=n;++i){
        ++cnt[s[i]-'a'];
    }int ed=-1;
    for (int i=0;i<26;++i) {
        if (k<=cnt[i]) {ed=i;break;}k-=cnt[i];
    }
    for (int i=1;i<=n;++i){
        if (s[i]-'a'<ed) continue;
        if (s[i]-'a'==ed&&k) {--k;continue;}
        s1[++top]=s[i];
    }printf("%s",s1+1);
    return 0;
}