BZOJ3744 Gty的妹子序列

  1 /**************************************************************
  2     Problem: 3744
  3     User: rausen
  4     Language: C++
  5     Result: Accepted
  6     Time:10876 ms
  7     Memory:50872 kb
  8 ****************************************************************/
  9  
 10 #include <cstdio>
 11 #include <cmath>
 12 #include <cctype>
 13 #include <cstring>
 14 #include <algorithm>
 15  
 16 #define lowbit(x) x & -x
 17 using namespace std;
 18  
 19 const int N = 50005;
 20 const int B = 250;
 21 int n, m;
 22 int T, block, size;
 23 int pos[N], st[B];
 24 int BIT[N], vis[N];
 25 int ans[B][B];
 26 int cnt[B][N];
 27 int a[N], b[N];
 28  
 29 inline int read() {
 30     int x = 0;
 31     char ch = getchar();
 32     while (!isdigit(ch))
 33         ch = getchar();
 34     while (isdigit(ch)) {
 35         x = x * 10 + ch - ‘0‘;
 36         ch = getchar();
 37     }
 38     return x;
 39 }
 40  
 41 inline int find(const int x) {
 42     int l = 1, r = n + 1, mid;
 43     while (l + 1 < r) {
 44         mid = (l + r) >> 1;
 45         if (b[mid] <= x) l = mid;
 46         else r = mid;
 47     }
 48     return l;
 49 }
 50  
 51 inline void add(int x){
 52     while (x <= n) {
 53         if (vis[x] != T) vis[x] = T, BIT[x] = 1;
 54         else ++BIT[x];
 55         x += lowbit(x);
 56     }
 57 }
 58  
 59 inline int query(int x) {
 60     int res = 0;
 61     while(x) {
 62         if (vis[x] == T)
 63             res += BIT[x];
 64         x -= lowbit(x);
 65     }
 66     return res;
 67 }
 68  
 69 int Work(int l, int r) {
 70     ++T;
 71     if (pos[l] == pos[r]) {
 72         int res = 0;
 73         for (; r >= l; --r)
 74             res += query(a[r] - 1), add(a[r]);
 75         return res;
 76     }
 77     int res, cnt_all, i;
 78     res = ans[pos[l] + 1][pos[r] - 1];
 79     cnt_all = st[pos[r]] - st[pos[l] + 1];
 80     for (i = st[pos[l] + 1] - 1; i >= l; --i) {
 81         res += query(a[i] - 1) + cnt[pos[r] - 1][a[i] - 1] - cnt[pos[l]][a[i] - 1];
 82         add(a[i]), ++cnt_all;
 83     }
 84     for (i = st[pos[r]]; i <= r; ++i) {
 85         res += cnt_all - query(a[i]) - cnt[pos[r] - 1][a[i]] + cnt[pos[l]][a[i]];
 86         add(a[i]), ++cnt_all;
 87     }
 88     return res;
 89 }
 90  
 91 void Block() {
 92     int i;
 93     size = (int) sqrt(n);
 94     for (i = 1; i <= n; ++i)
 95         pos[i] = (i - 1) / size + 1;
 96     block = pos[n];
 97     for (i = 1; i <= block; ++i)
 98         st[i] = size * (i - 1) + 1;
 99     st[block + 1] = n + 1;
100 }
101  
102 void pre_work() {
103     int cnt_now, cnt_all, i, j, k;
104     for (i = 1; i <= block; ++i) {
105         cnt_now = cnt_all = 0, ++T;
106         memcpy(cnt[i], cnt[i - 1], sizeof(cnt[i]));
107         for (j = i; j <= block; ++j)
108             for (k = st[j]; k <= st[j + 1] - 1; ++k) {
109                 cnt_now += cnt_all - query(a[k]);
110                 ans[i][j] = cnt_now;
111                 add(a[k]);
112                 ++cnt_all, ++cnt[j][a[k]];
113             }
114     }
115     for (i = 1; i <= block; ++i)
116         for (j = 2; j <= n; ++j)
117             cnt[i][j] += cnt[i][j - 1];
118 }
119  
120 int main() {
121     int i;
122     n = read();
123     for (i = 1; i <= n; ++i)
124         a[i] = b[i] = read();
125     m = read();
126     sort(b + 1, b + n + 1);
127     for (i = 1; i <= n; ++i)
128         a[i] = find(a[i]);
129     Block();
130     pre_work();
131     int L, R, ans = 0;
132     while (m--) {
133         L = read() ^ ans, R = read() ^ ans;
134         printf("%d\n", ans = Work(L, R));
135     }
136     return 0;
137 }