P22555 [USACO] Hungry cow
省选
题目描述

Note: The time limit for this problem is 6s, three times the default. The
memory limit for this problem is 512MB, twice the default.

Bessie is a hungry cow. Each day, for dinner, if there is a haybale in the barn,
she will eat one haybale. Farmer John does not want Bessie to starve, so some
days he sends a delivery of haybales, which arrive in the morning (before
dinner). In particular, on day $d_i$, Farmer John sends a delivery of $b_i$
haybales ($1\leq d_i \leq 10^{14}$, $0\leq b_i \leq 10^9$).

Process $U$ ($1\le U\le 10^5$) updates as follows: Given a pair $(d, b)$,
update the number of haybales arriving on day $d$ to $b$. After each update,
output the sum of all days on which Bessie eats haybales modulo
$10^9+7$.

INPUT FORMAT (input arrives from the terminal / stdin):
$U$, followed by $U$ lines containing the updates.

OUTPUT FORMAT (print output to the terminal / stdout):
The sum after each update modulo $10^9+7$.

SAMPLE INPUT:
3
4 3
1 5
1 2
SAMPLE OUTPUT:
15
36
18

Answers after each update:

4+5+6=15
1+2+3+4+5+6+7+8=36
1+2+4+5+6=18

SAMPLE INPUT:
9
1 89
30 7
101 26
1 24
5 1
60 4
5 10
101 0
1 200
SAMPLE OUTPUT:
4005
4656
7607
3482
3507
3753
4058
1107
24531

SCORING:
Input 3: $U\le 5000$Inputs 4-10: Updates only increase the number of haybales arriving on day
$d$.Inputs 11-22: No additional constraints.

Problem credits: Brandon Wang and Benjamin Qi

输入格式

见题面

输出格式

见题面

样例输入
3 4 3 1 5 1 2
样例输出
15 36 18