HDU 2037 今年暑假不AC

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

struct show
{
    int start;
    int end;
};
bool cmp(show a, show b) {
    return a.end < b.end;
}
show a[101];
int f1[101];
int f2[101];

int dp(int n, show *a) {
    memset(f1, 0, sizeof(f1));
    memset(f2, 0, sizeof(f2));
    

    for (int i = 0; i < n;i++) {
        for (int j = a[i].end; j <=100; j++) 
            f2[j] = max(f1[j], f1[a[i].start] + 1);
        memcpy(f1, f2, sizeof(f2));
    }
    return f1[100];
}



int main() {
    int n;
    while (cin>>n&&n!=0)
    {
        for (int i = 0; i < n; i++)
            cin >> a[i].start >> a[i].end;
        sort(a, a + n, cmp);
        cout << dp(n, a) << endl;
    }

}