poj 1065 Wooden Sticks

/*
先按l排序 再每次找出一段最长的递增序列！
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct stick{
    int l, w;
}st[50010];

bool used[50010];

int cmp(const void *a, const void *b){
    stick *s1 = (stick*)a, *s2 = (stick*)b;
    if(s1 -> l == s2 -> l)
        return s1 -> w - s2 -> w;
    return s1 -> l - s2 -> l;
}
int main(){
    int t ,n;
    scanf("%d",&t);
    while( t-- ){
        memset(used, false, sizeof(used));
        scanf("%d",&n);
        for(int i = 0; i < n; ++i){
            scanf("%d%d",&st[i].l, &st[i].w);
        }
        qsort(st, n, sizeof(st[0]), cmp);
        //for(int i = 0; i < n; ++i){
        //    printf("%d %d\n",st[i].l, st[i].w);
        //}
        int i,j, ans = 0;
        stick temp;
        for(i = 0; i < n; ++i){//关键代码
            if( !used[i] ){
                ans++;
                used[i] = true;
                temp = st[i];
                for(j = i + 1; j < n; j++){
                    if(st[j].l >= temp.l && st[j].w >= temp.w && !used[j]){
                        temp = st[j];
                        used[j] = true;
                    }
                }
            }
        }
        printf("%d\n",ans);
    }    
    return 0;
}