解码异或后的排列延伸(数学问题)

Posted 2021-06-06 秦枫-_-

接着利用异或的性质即可得出原数组

class Solution {
    public int[] decode(int[] encoded) {
    int []res=new int[encoded.length+1];
    int n=encoded.length+1;
    int first=0;
   for(int i=1;i<=n;i++){
       first^=i;
   }
   int dfirst=0;
   for(int i = 1; i < n - 1; i += 2){
       dfirst^=encoded[i];
   }
   first^=dfirst;
   res[0]=first;
    for(int m=0;m<encoded.length;m++){
        res[m+1]=res[m]^encoded[m];
    }
    return res;
    }
    
}