hdu1051 Wooden Sticks

题目：http://acm.hdu.edu.cn/showproblem.php?pid=1051

大意：求最少升序序列的个数。

 

#include <cstdio>

#include <cstring>

#include <algorithm>

#define N 5000 + 5

using namespace std;

struct node {

    int x, y;

    bool operator < (const node& t) const {

        return (x < t.x) || (x == t.x && y < t.y);

    }

} f[N];

bool mark[N];

int main()

{

    int T, n, tw, ans, i, j;

    scanf("%d", &T);

    while (T--) {

        scanf("%d", &n);

        for (i = 0; i < n; i++) scanf("%d%d", &f[i].x, &f[i].y);

        sort(f, f + n);

        memset(mark, false, sizeof(mark));

        ans = 0;

        for (i = 0; i < n; i++)

            if (!mark[i]) {

                tw = f[i].y;

                mark[i] = true;

                ans++;

                for (j = i + 1; j < n; j++)

                    if (!mark[j] && f[j].y >= tw) {

                        tw = f[j].y;

                        mark[j] = true;

                    }

            }

        printf("%d\n", ans);

    }

    return 0;

}