【正经题解】有趣的软件

很水，小DP

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
template<typename T>
inline void rd(T &x)
{
    x = 0;
    char c = getchar();
    bool f = 0;
    while (!isdigit(c))
    {
        if (c == '-')
        {
            f = 1;
        }
        c = getchar();
    }
    while (isdigit(c))
    {
        x = (x << 3) + (x << 1) + (c ^ '0');
        c = getchar();
    }
    if (f)
    {
        x = ~(x - 1);
    }
}
template<typename T, typename...Args>
inline void rd(T &x, Args&...args)
{
    rd(x);
    rd(args...);
}
inline void wt(int x)
{
    if (x < 0)
    {
        putchar('-');
        x = -x;
    }
    if (x > 9)
    {
        wt(x / 10);
    }
    putchar(x % 10 + '0');
}

#define pc(x) putchar(x)
#define wtl(x) wt(x), pc('\n')
#define kg pc(' ')
#define hh pc('\n')
int f[110][10];

signed main()
{
    char s[110];
    scanf("%s", s + 1);
    int l = strlen(s + 1);
    f[0][1] = 1;
    for (int i = 1; i <= l; i++)
    {
        if (s[i] >= 'A' && s[i] <= 'Z')
        {
            f[i][1] = min(f[i - 1][1] + 1, f[i - 1][0] + 2);
            f[i][0] = min(f[i - 1][0] + 2, f[i - 1][1] + 2);
        }
        else
        {
            f[i][1] = f[i - 1][1] + 2;
            f[i][0] = f[i - 1][0] + 1;
        }
    }
    wtl(min(f[l][0], f[l][1] + 1));
    return 0;
}

能AC。
加油！！