Python解决codeforces ---- 4
第一题 10A
A. Power Consumption Calculation
time limit per test 1 second
memory limit per test 256 megabytes
input standard input
output standard output
Tom is interested in power consumption of his favourite laptop. His laptop has three modes. In normal mode laptop consumes P1 watt per minute. T1 minutes after Tom moved the mouse or touched the keyboard for the last time, a screensaver starts and power consumption changes to P2 watt per minute. Finally, after T2 minutes from the start of the screensaver, laptop switches to the "sleep" mode and consumes P3 watt per minute. If Tom moves the mouse or touches the keyboard when the laptop is in the second or in the third mode, it switches to the first (normal) mode. Tom's work with the laptop can be divided into n time periods [l1, r1], [l2, r2], ..., [ln, rn]. During each interval Tom continuously moves the mouse and presses buttons on the keyboard. Between the periods Tom stays away from the laptop. Find out the total amount of power consumed by the laptop during the period [l1, rn].
Input
The first line contains 6 integer numbers n, P1, P2, P3, T1, T2 (1 ≤ n ≤ 100, 0 ≤ P1, P2, P3 ≤ 100, 1 ≤ T1, T2 ≤ 60). The following nlines contain description of Tom's work. Each i-th of these lines contains two space-separated integers li and ri (0 ≤ li < ri ≤ 1440, ri < li + 1 for i < n), which stand for the start and the end of the i-th period of work.
Output
Output the answer to the problem.
Sample test(s)
input
1 3 2 1 5 10
0 10
output
30
input
2 8 4 2 5 10
20 30
50 100
output
570
题意：电脑有三种模式，正常模式每分钟耗电p1，如果没有使用电脑t1分钟后变成第二种模式每分钟耗电p2，如果还是没有使用电脑t2分钟后变成第三种模式每分钟耗电p3。给定n个区间，每一个区间是正常模式，每个区间的间隔是没有使用，问总的耗电是多少
思路：直接暴力枚举
代码：
[python]
# input
list = raw_input().split()
n,p1,p2,t1,t2,t3 = map(int , list)
# solve
ans = 0
pre = -1
while n > 0:
n -= 1
list = raw_input().split()
start,end = map(int , list)
ans += (end-start)*p1
if pre != -1:
x = start-pre
if x > t1:
ans += t1*p1
x -= t1
if x > t2:
ans += t2*p2
x -= t2
ans += x*p3
else:
ans += x*p2
else:
ans += x*p1
pre = end
print ans
第二题 11A
A. Increasing Sequence
time limit per test 1 second
memory limit per test 64 megabytes
input standard input
output standard output
A sequence a0, a1, ..., at - 1 is called increasing if ai - 1 < ai for each i: 0 < i < t.
You are given a sequence b0, b1, ..., bn - 1 and a positive integer d. In each move you may choose one element of the given sequence and add d to it. What is the least number of moves required to make the given sequence increasing?
Input
The first line of the input contains two integer numbers n and d (2 ≤ n ≤ 2000, 1 ≤ d ≤ 106). The second line contains space separated sequence b0, b1, ..., bn - 1 (1 ≤ bi ≤ 106).
Output
Output the minimal number of moves needed to make the sequence increasing.
Sample test(s)
input
4 2
1 3 3 2
output
3
题意：给定n个数的序列，现在要把这个序列变成递增的序列，满足ai < ai+1，现在规定每次可以选择一个数来增加d，问最少需要几次
思路：枚举每一个数求个数即可
代码：
[python]
# input
n,d = map(int , raw_input().split())
list = map(int , raw_input().split())
# getAns
ans = 0
for i in range(1,len(list)):
if list[i] <= list[i-1]:
x = (list[i-1]-list[i])/d+1
list[i] += x*d
ans += x
print ans
第三题 12A
A. Super Agent
time limit per test 2 seconds
memory limit per test 256 megabytes
input standard input
output standard output
There is a very secret base in Potatoland where potato mash is made according to a special recipe. The neighbours from Porridgia decided to seize this recipe and to sell it to Pilauland. For this mission they have been preparing special agent Pearlo for many years. When, finally, Pearlo learned all secrets of espionage, he penetrated into the Potatoland territory and reached the secret base.
Now he is standing at the entrance, but to get inside he need to pass combination lock. Minute ago one of the workers entered the password on the terminal and opened the door. The terminal is a square digital keyboard 3 × 3 with digits from 1 to 9.
Pearlo knows that the password consists from distinct digits and is probably symmetric with respect to the central button of the terminal. He has heat sensor which allowed him to detect the digits which the worker pressed. Now he wants to check whether the password entered by the worker is symmetric with respect to the central button of the terminal. This fact can Help Pearlo to reduce the number of different possible password combinations.
Input
Input contains the matrix of three rows of three symbols each. Symbol «X» means that the corresponding button was pressed, and «.» means that is was not pressed. The matrix may contain no «X», also it may contain no «.».
Output
Print YES if the password is symmetric with respect to the central button of the terminal and NO otherwise.
Sample test(s)
input
XX.
...
.XX
output
<
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