LeetCode每日一题(1734. 解码异或后的排列)

直接上图

思路

代码

class Solution {
    public int[] decode(int[] encoded) {
      int n = encoded.length;
        int[] decode = new int[n + 1];
        //求1到n+1的所有数异或
        int all = 0;
        for (int i = 0; i <= n + 1; i++) {
            all ^= i;
        }
        //求编码后的索引为奇数位的异或
        int odd = encoded[1];
        for (int j = 3; j < n; j += 2) {
            odd ^= encoded[j];
        }
        //求编码前的第一位数
        int first = odd ^ all;
        decode[0] = first;
        //遍历求出其他的编码前的数
        for (int z = 0; z < n; z++) {
            decode[z + 1] = decode[z] ^ encoded[z];
        }
        return decode;
    }
}