POJ 1065 Wooden Sticks（贪心法）

题目链接
http://bailian.openjudge.cn/practice/1065/

思路：贪心法。对所有wood按照len升序、weight升序排序。对于每一个wood，向后查找，尽可能找到能覆盖它的wood，并将覆盖它的wood标进行加工（不需要额外的setup time）。遍历时，如果当前wood未加工，setup time 加1

#include <iostream>
#include <algorithm>
#include <cstdio>

using namespace std;

int T, N;
int used[6000];

struct wood
{
    int len;
    int weight;
}w[6000];

bool cmp(wood a, wood b)
{
    return (a.len<b.len || (a.len==b.len&&a.weight<b.weight));
}

int main()
{
    scanf("%d", &T);
    while(T--)
    {
        int setup = 0;

        scanf("%d", &N);
        for(int i=0;i<N;i++)
        {
            scanf("%d%d", &w[i].len, &w[i].weight);
            used[i] = 0;
        }

        sort(w, w+N, cmp);      // x升序排列，x相同时，按照y升序排列

        for(int i=0;i<N;i++)
        {
            if(used[i] == 0)
            {
                setup++;
                // 从后面找能覆盖的，贪心法
                int len = w[i].len, weight = w[i].weight;
                for(int j=i+1;j<N;j++)
                {
                    if(used[j]==0 && w[j].len>=len && w[j].weight>=weight)
                    {
                        used[j] = 1;
                        len = w[j].len;
                        weight = w[j].weight;
                    }
                }
            }
        }

        printf("%d\n", setup);
    }
    return 0;
}