BZOJ 3261: 最大异或和

 1 #include <cstdio>
 2 
 3 const int mxn = 1E6;
 4 const int siz = 2E7;
 5 
 6 int n, m;
 7  
 8 int a[mxn];
 9 int b[mxn];
10 
11 int tot;
12 int rt[mxn];
13 int ls[siz];
14 int rs[siz];
15 int sm[siz];
16 
17 void insert(int &t, int p, int c, int d)
18 {
19     t = ++tot;
20     
21     ls[t] = ls[p];
22     rs[t] = rs[p];
23     sm[t] = sm[p] + 1;
24     
25     if (c < 0)return;
26     
27     if ((d >> c) & 1)
28         insert(rs[t], rs[p], c - 1, d);
29     else
30         insert(ls[t], ls[p], c - 1, d);
31 }
32 
33 int query(int a, int b, int c, int d)
34 {
35     if (c < 0)return 0;
36     
37     int bit = (d >> c) & 1;
38     
39     if (bit)
40     {
41         if (sm[ls[a]] - sm[ls[b]])
42             return query(ls[a], ls[b], c - 1, d) | (1 << c);
43         else
44             return query(rs[a], rs[b], c - 1, d);
45     }
46     else
47     {
48         if (sm[rs[a]] - sm[rs[b]])
49             return query(rs[a], rs[b], c - 1, d) | (1 << c);
50         else
51             return query(ls[a], ls[b], c - 1, d);
52     }
53 }
54 
55 signed main(void)
56 {
57     scanf("%d%d", &n, &m); ++n;
58     
59     for (int i = 2; i <= n; ++i)
60         scanf("%d", a + i);
61     
62     for (int i = 1; i <= n; ++i)
63         b[i] = b[i - 1] ^ a[i];
64     
65     for (int i = 1; i <= n; ++i)
66         insert(rt[i], rt[i - 1], 25, b[i]);
67     
68     for (int i = 1; i <= m; ++i)
69     {
70         static char s[5];
71         
72         scanf("%s", s);
73         
74         if (s[0] == ‘A‘)
75         {
76             scanf("%d", a + ++n);
77             b[n] = b[n - 1] ^ a[n];
78             insert(rt[n], rt[n - 1], 25, b[n]);
79         }
80         else
81         {
82             int l, r, k;
83             scanf("%d%d%d", &l, &r, &k);
84             printf("%d\n", query(rt[r], rt[l - 1], 25, k ^ b[n]));
85         }
86     }
87 }