A Simple Problem with Integers
点我看原题^_^http://poj.org/problem?id=3468
| Time Limit: 5000MS |
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Memory Limit: 131072K |
| Total Submissions: 94280 |
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Accepted: 29370 |
| Case Time Limit: 2000MS |
Description
You have N integers, A1, A2, ... , AN. You need to deal with two kinds of operations. One type of operation is to add some given number to each number in a given interval. The other is to ask for the sum of numbers in a given interval.
Input
The first line contains two numbers N and Q. 1 ≤ N,Q ≤ 100000.
The second line contains N numbers, the initial values of A1, A2, ... , AN. -1000000000 ≤ Ai ≤ 1000000000.
Each of the next Q lines represents an operation.
"C a b c" means adding c to each of Aa, Aa+1, ... , Ab. -10000 ≤ c ≤ 10000.
"Q a b" means querying the sum of Aa, Aa+1, ... , Ab.
Output
You need to answer all Q commands in order. One answer in a line.
Sample Input
10 5
1 2 3 4 5 6 7 8 9 10
Q 4 4
Q 1 10
Q 2 4
C 3 6 3
Q 2 4
Sample Output
4
55
9
15
解题思路：
简单线段树区间求和加减题，套模版即可。
先建树，每个节点为该节点孩子的和，求和只需访问区间相应的节点；但是在区间加减时，直接给该节点+num*（以该节点为根的树的叶子的个数），先不用给叶子加（这就是线段树速度快的原因），当哪天你要去访问该节点的孩子或叶子，再去给它加减。这种题套模版多做题就OK了。
代码实现：
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