HDU 3333 Turing Tree (树状数组)

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。

 //#pragma comment(linker, "/STACK:102400000, 102400000")
 #include <algorithm>
 #include <iostream>
 #include <cstdlib>
 #include <cstring>
 #include <cstdio>
 #include <vector>
 #include <cmath>
 #include <ctime>
 #include <list>
 #include <set>
 #include <map>
 using namespace std;
 typedef long long LL;
 typedef pair <int, int> P;
 const int N = 1e5 + ;
 struct query {
     int l, r, pos;
     bool operator <(const query &cmp) const {
         return r < cmp.r;
     }
 }q[N];
 int a[];
 LL bit[], ans[N];
 map <int, int> mp;

 void update(int i, LL val) {
     for( ; i <= ; i += (i&-i))
         bit[i] += val;
 }

 LL sum(int i) {
     LL s = ;
     for( ; i >= ; i -= (i&-i))
         s += (LL)bit[i];
     return s;
 }

 int main()
 {
     int t, n, m;
     scanf("%d", &t);
     while(t--) {
         memset(bit, , sizeof(bit));
         mp.clear();
         scanf("%d", &n);
         for(int i = ; i <= n; ++i) {
             scanf("%d", a + i);
         }
         scanf("%d", &m);
         for(int i = ; i <= m; ++i) {
             scanf("%d %d", &q[i].l, &q[i].r);
             q[i].pos = i;
         }
         sort(q + , q + m + );
         int index = ;
         for(int i = ; i <= n; ++i) {
             if(mp.find(a[i]) != mp.end()) { //a[i]曾经出现过
                 update(mp[a[i]], (LL)-a[i]);
             }
             mp[a[i]] = i;
             update(i, a[i]);
             while(q[index].r == i && index <= m) {
                 ans[q[index].pos] = sum(q[index].r) - sum(q[index].l - );
                 ++index;
             }
         }
         for(int i = ; i <= m; ++i) {
             printf("%lld\n", ans[i]);
         }
     }
     return ;
 }