题解 | #拦截导弹#

就是最长上升子序列的问题，把上升改成不减就行了

#include <iostream>
#include <algorithm>
using namespace std;

const int N = 30;

int a[N], f[N];
int n;

int main()
{
    cin >> n;
    for (int i = 1; i <= n; ++i)
        cin >> a[i], f[i] = 1;
    
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j < i; ++j)
            if (a[j] >= a[i])
                f[i] = max(f[i], f[j] + 1);
    
    int res = 0;
    for (int i = 1; i <= n; ++i)
        res = max(res , f[i]);
    cout << res << endl;
    return 0;
}