树状数组入门之 hdu 1166

第一道树状数组。。。入门。。。线段树做法：代码见这里

 1 //  [4/7/2014 Sjm]
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstdlib>
 5 #include <string>
 6 using namespace std;
 7 const int MAX_N = 50000;
 8 int bit[MAX_N + 1], n;
 9 
10 int mySum(int i)
11 {
12     int sum = 0;
13     while (i>0){
14         sum += bit[i];
15         i -= (i&(-i));
16     }
17     return sum;
18 }
19 
20 void myAdd(int i, int x)
21 {
22     while (i<=n) {
23         bit[i] += x;
24         i += (i&(-i));
25     }
26 }
27 
28 int main()
29 {
30     //freopen("input.txt", "r", stdin);
31     //freopen("output.txt", "w", stdout);
32     int T;
33     scanf("%d", &T);
34     for (int i = 1; i <= T; i++)
35     {
36         memset(bit, 0, sizeof(bit));
37         printf("Case %d:
", i);
38         scanf("%d", &n);
39         for (int j = 1; j <= n; j++) {
40             int x;
41             scanf("%d", &x);
42             myAdd(j, x);
43         }
44         string str;
45         while (cin>>str && ('E' != str[0]))
46         {
47             int a, b;
48             scanf("%d %d", &a, &b);
49             if ('Q' == str[0])
50                 printf("%d
", mySum(b) - mySum(a-1));
51             else {
52                 if ('A' == str[0]) myAdd(a, b);
53                 else myAdd(a, -b);
54             }
55         }
56     }
57     return 0;
58 }

树状数组入门 之 hdu 1166

树状数组入门之 hdu 1166