HDU 3333 Turing Tree (树状数组)

Posted 2020-08-11 Recoder

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=3333

题意就是询问区间不同数字的和。

比较经典的树状数组应用。

 1 //#pragma comment(linker, "/STACK:102400000, 102400000")
 2 #include <algorithm>
 3 #include <iostream>
 4 #include <cstdlib>
 5 #include <cstring>
 6 #include <cstdio>
 7 #include <vector>
 8 #include <cmath>
 9 #include <ctime>
10 #include <list>
11 #include <set>
12 #include <map>
13 using namespace std;
14 typedef long long LL;
15 typedef pair <int, int> P;
16 const int N = 1e5 + 5;
17 struct query {
18     int l, r, pos;
19     bool operator <(const query &cmp) const {
20         return r < cmp.r;
21     }
22 }q[N];
23 int a[30005];
24 LL bit[30005], ans[N];
25 map <int, int> mp;
26 
27 void update(int i, LL val) {
28     for( ; i <= 30000; i += (i&-i))
29         bit[i] += val;
30 }
31 
32 LL sum(int i) {
33     LL s = 0;
34     for( ; i >= 1; i -= (i&-i))
35         s += (LL)bit[i];
36     return s;
37 }
38 
39 int main()
40 {
41     int t, n, m;
42     scanf("%d", &t);
43     while(t--) {
44         memset(bit, 0, sizeof(bit));
45         mp.clear();
46         scanf("%d", &n);
47         for(int i = 1; i <= n; ++i) {
48             scanf("%d", a + i);
49         }
50         scanf("%d", &m);
51         for(int i = 1; i <= m; ++i) {
52             scanf("%d %d", &q[i].l, &q[i].r);
53             q[i].pos = i;
54         }
55         sort(q + 1, q + m + 1);
56         int index = 1;
57         for(int i = 1; i <= n; ++i) {
58             if(mp.find(a[i]) != mp.end()) { //a[i]曾经出现过
59                 update(mp[a[i]], (LL)-a[i]);
60             }
61             mp[a[i]] = i;
62             update(i, a[i]);
63             while(q[index].r == i && index <= m) {
64                 ans[q[index].pos] = sum(q[index].r) - sum(q[index].l - 1);
65                 ++index;
66             }
67         }
68         for(int i = 1; i <= m; ++i) {
69             printf("%lld\n", ans[i]);
70         }
71     }
72     return 0;
73 }