什么意思？

#include <iostream>
using namespace std;
int main()  {
    const int SIZE = 100;
    int height[SIZE], num[SIZE], n, ans;
    cin>>n;
    for (int i = 0; i < n; i++) {
        cin>>height[i];
        num[i] = 1;
        for (int j = 0; j < i; j++) {
            if ((height[j] < height[i]) && (num[j] >= num[i]))
                num[i] = num[j]+1;
        }
    }
    ans = 0;
    for (int i = 0; i < n; i++) {
        if (num[i] > ans)
            ans = num[i];
    }
    cout<<ans<<endl;
}



这段代码什么意思？