HDU 1051 Wooden Sticks

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

#define N 5000

struct Stick {
    int l, w;
} s[N];
bool vis[N];

bool cmp(Stick a, Stick b) {
    return a.l < b.l || a.l == b.l && a.w < b.w;
}

int main() {
    int t, n, ans;
    scanf("%d", &t);
    while (t--) {
        scanf("%d", &n);
        for (int i = 0; i < n; i++) {
            scanf("%d%d", &s[i].l, &s[i].w);
            vis[i] = 0;
        }
        sort(s, s + n, cmp);
        ans = 0;
        for (int i = 0; i < n; i++) {
            if (!vis[i]) {
                for (int j = i + 1, mn = s[i].w; j < n; j++) {
                    if (!vis[j] && s[j].w >= mn) {
                        mn = s[j].w;
                        vis[j] = 1;
                    }
                }
                ans++;
            }
        }
        printf("%d\n", ans);
    }
    return 0;
}