Codeforces 835B The number on the board (贪心)

题目链接

CF 835B

题目大意

分析

代码

#include <bits/stdc++.h>using namespace std;int num[100010];int main(){    string ch;    int k,ans,len,i,cnt,p,t;    cin>>k;    cin>>ch;    len=ch.length();    cnt=0;    for (i=0;i<len;i++)        cnt+=(ch[i]-'0');    if (cnt>=k)        cout<<0<<endl;    else    {        p=k-cnt;        for (i=0;i<len;i++)            num[i]=9-ch[i]+'0';        sort(num,num+len);        t=len-1;        ans=0;        while (p>0)        {            p-=num[t--];            ans++;        }        cout<<ans<<endl;    }    return 0;}