题解 | 小红的大小写字母

#include <stdio.h>

int main()
{
    char ch[100005];
    int n,k;
    int upper=0,lower=0;
    int sum;
    scanf("%d%d",&n,&k);
    scanf("%s",ch);
    for(int i=0;i<n;i++)
    {
        if(ch[i]>='A'&&ch[i]<='Z')
        upper++;
        else if(ch[i]>='a'&&ch[i]<='z')
        lower++;
    }
    int change=k;
    if(k<=lower)
    {
        sum=upper+change;
        change=0;
    }
    else
    {
        sum=lower+upper;
        change=change-lower;
    }
    if(change%2==1)
        sum--;
    printf("%d",sum);
    return 0;
}