poj 2184 Cow Exhibition

#include<bits/stdc++.h>
using namespace std;
const int N = 110;
int dp[N],m,n,bx0;
struct Cow{
    int ts,tf,sum_sf;
}b[N];
bool cmp(Cow a,Cow b){return a.sum_sf>b.sum_sf;}
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> b[i].ts >> b[i].tf;
        b[i].sum_sf = b[i].ts + b[i].tf;
    }
    sort(b + 1, b + n + 1, cmp);
    for (int i = 1; i <= n; i++) {
       // cout << b[i].ts << " " << b[i].tf << " " << b[i].sum_sf << endl;
        if (b[i].sum_sf <= 0) {
            bx0 = i - 1;
            break;
        }
    }
    //cout << bx0 << endl;
    for (int i = 1; i <= bx0; i++) {
        for (int j = bx0; j >= i; j--) {
            dp[j]=max(dp[j],dp[j-i]+b[i].sum_sf);
        }
    }
    cout<<dp[n]<<endl;
    return 0;
}