POJ 1065 (贪心法)

/*
思路：首先对木棒排序，按length升序排序，length相同，则按weight升序排序
然后在weight中通过贪心法找有多少个递增序列
*/
#include <iostream>
#include <algorithm>
using namespace std;

const int MAX_NUM = 5002;
struct stick{
	int len, wgt;
}stk[MAX_NUM];
bool vis[MAX_NUM];

bool cmp(const stick& stk1, const stick& stk2)
{
	if (stk1.len < stk2.len) 
		return true;
	else if (stk1.len == stk2.len) 
		return stk1.wgt < stk2.wgt;
	else return false;
}

int main()
{
	int c, n, i, j, cnt, wgt;
	scanf("%d", &c);
	while (c--){
		scanf("%d", &n);
		cnt = 0;
		memset(vis, 0, sizeof(vis));
		for (i = 0; i < n; ++i)
			scanf("%d%d", &stk[i].len, &stk[i].wgt);
		sort(stk, stk+n, cmp);
		for (i = 0; i < n; ++i){
			if (!vis[i]){
				vis[i] = true, cnt++;
				wgt = stk[i].wgt;
				for (j = i+1; j < n; ++j){
					if (!vis[j] && stk[j].wgt >= wgt)
						vis[j] = true, wgt = stk[j].wgt; //记录当前序列最大值
				}
			}
		}
		printf("%d\n", cnt);
	}
	return 0;
}