NYOJ 16 矩形嵌套

题目：矩形嵌套

import java.util.Scanner;
public class Main {//深搜超时---TimeLimitExceeded	 --	 --	java	2013-07-23 22:55:29
	static F f[];
	static int n,max;
	public static void main(String[] args) {
		Scanner input=new Scanner(System.in);
		int N=input.nextInt();
		while(N-->0){
			n=input.nextInt();
			max=0;
			f=new F[n];
			for(int i=0;i<n;i++){
				int x=input.nextInt();
				int y=input.nextInt();
				f[i]=new F(x,y);
			}
			for(int i=0;i<n;i++){
				f[i].ok=false;
				dfs(f[i].wide,f[i].high,1);
				f[i].ok=true;
			}
			System.out.println(max);
		}
	}
	
	private static void dfs(int wide, int high, int sum) {//递归深度搜索
		if(sum>max)//记录最大值
			max=sum;
		for(int i=0;i<n;i++){
			if(f[i].ok&&(f[i].wide<wide&&f[i].high<high||f[i].wide<high&&f[i].high<wide)){
				f[i].ok=false;
				dfs(f[i].wide,f[i].high,sum+1);
				f[i].ok=true;
			}
		}
	}
}
class F{//存储长和宽，以及是否被用过
	int wide,high;
	boolean ok=true;
	F(int wide,int high){
		this.wide=wide;
		this.high=high;
	}
	F(){
	}
}

import java.util.Scanner;
public class Main{//动态规划，Accepted 47MS 739java2013-07-23 23:39:06
	static int g[][],t[],n;
	public static void main(String[] args) {
		Scanner input=new Scanner(System.in);
		int N=input.nextInt();
		while(N-->0){
			n=input.nextInt();
			int a[]=new int[n];
			int b[]=new int[n];
			g=new int[n][n];
			t=new int[n];
			for(int i=0;i<n;i++){
				a[i]=input.nextInt();
				b[i]=input.nextInt();
			}
			for(int i=0;i<n;i++)
	            for(int j=0;j<n;j++)
	                if((a[i]>a[j]&&b[i]>b[j])||(a[i]>b[j]&&b[i]>a[j])) 
	                    g[i][j]=1;
			int max=-1;
			for(int i=0;i<n;++i)
	            if(dp(i)>max)
	                max=dp(i);
			System.out.println(max);
			
		}
		
	}
	private static int dp(int i) {
		
		int ans=t[i];
	    if(ans>0)
	        return ans;
	    ans=1;
	    for(int j=0;j<n;++j)
	        if(g[i][j]!=0)
	            if(ans<dp(j)+1){
	                ans=dp(j)+1;
	                t[i]=ans;
	            }
	    return ans;
	}
}