hdu-5014-Number Sequence-XiAn网络赛1008-水题

思路：既然是求两个数的异或运算之和，且由于数字不重复，那么肯定两个数异或的结果数字越大越好，即异或后从ai二进制的最高位后全是1。

具体思路看代码：

AC代码：

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <queue>
 4 #include <vector>
 5 #include <algorithm>
 6 using namespace std;
 7 int bit[17];
 8 int brr[100005];
 9 int n;
10 void init()
11 {
12     bit[0] = 1;
13     for(int i = 0; i <= 16; i++) {
14         bit[i+1] = 2<<i;
15     }
16 }
17 int arr[100005];
18 void deal(int x)
19 {
20     for(int i = 0; i < n+10; i++) arr[i] = -1;
21     arr[0] = 0;
22     int k, le, xx;
23     while(x != 0){
24         if(x <= 0) return;
25         int pos = upper_bound(bit, bit+18, x) - bit - 1;
26         if(pos == 0) {
27             arr[0] = 1; arr[1] = 0;
28             return;
29         }
30         xx = x;
31         if(pos == 1) k = 0x00000003 ^ x;
32         else if(pos == 2) k = 0x00000007 ^ x;
33         else if(pos == 3) k = 0x0000000f ^ x;
34         else if(pos == 4) k = 0x0000001f ^ x;
35         else if(pos == 5) k = 0x0000003f ^ x;
36         else if(pos == 6) k = 0x0000007f ^ x;
37         else if(pos == 7) k = 0x000000ff ^ x;
38         else if(pos == 8) k = 0x000001ff ^ x;
39         else if(pos == 9) k = 0x000003ff ^ x;
40         else if(pos == 10) k = 0x000007ff ^ x;
41         else if(pos == 11) k = 0x00000fff ^ x;
42         else if(pos == 12) k = 0x00001fff ^ x;
43         else if(pos == 13) k = 0x00003fff ^ x;
44         else if(pos == 14) k = 0x00007fff ^ x;
45         else if(pos == 15) k = 0x0000ffff ^ x;
46         else if(pos == 16) k = 0x0001ffff ^ x;
47         le = k;
48         x = k - 1;
49         for(int i = xx; i >= k; i--) arr[i] = le++;
50     }
51 }
52 int main()
53 {
54     init();
55     while(scanf("%d", &n) != EOF) {
56         deal(n);
57         long long ans = 0;
58         for(int i = 0; i <= n; i++) {
59             int a; scanf("%d", &a);
60             brr[i] = arr[a];
61             ans += a ^ arr[a];
62         }
63         printf("%I64d\n%d", ans, brr[0]);
64         for(int i = 1; i <= n; i++) {
65             printf(" %d", brr[i]);
66         }
67         printf("\n");
68     }
69     return 0;
70 }

总结：QAQ比赛的时候看错题意了。。。。忽略了数字不重复的条件，导致想了好久。。。。