354. 俄罗斯套娃信封问题

class Solution {
    public int maxEnvelopes(int[][] envelopes) {
        if(envelopes.length==0)
            return 0;
       for(int i=1;i<envelopes.length;i++)
       {
            int []temp=envelopes[i];
		           int j=i-1;
		           for(;j>=0&&envelopes[j][0]>temp[0];j--)
		           {	   
		        		   envelopes[j+1]=envelopes[j];
		           }
		           if(j<0)
		               envelopes[0]=temp;
		           else
		        	   envelopes[j+1]=temp;
       }
        int []dp=new int[envelopes.length];
        dp[0]=1;
        for(int i=1;i<envelopes.length;i++)
        {
            int []temp=envelopes[i];
            int max=0;
            for(int j=i-1;j>=0;j--)
            {
                if(envelopes[j][0]<temp[0]&&envelopes[j][1]<temp[1])
                {
                     max=Math.max(max,dp[j]);
                }
                
            }
            dp[i]=max+1;
        }
        Arrays.sort(dp);
        return dp[envelopes.length-1];
        
    }
}

class Solution {
    public int maxEnvelopes(int[][] envelopes) {
        if(envelopes == null || envelopes.length == 0) return 0;
        Arrays.sort(envelopes, new Comparator<int[]>(){
           @Override
           public int compare(int[] arr1, int[] arr2){
               if(arr1[0] == arr2[0]){
                  return arr2[1] - arr1[1];
               } else{
                  return arr1[0] - arr2[0];
               }
           }
        });
        
        int[] dp = new int[envelopes.length];   // the tail nums of length i;
        int len = 0;
        for(int[] envelope: envelopes){
            int index = Arrays.binarySearch(dp, 0, len, envelope[1]);
            if(index < 0){                  // do not contain this num, adding to tail
                index = -(index + 1);       // replace it with smaller one
            }
            dp[index] = envelope[1];
            if(index == len) len++;
        }
        return len; 
    }
}