Put the question requirements first, and explain them through the procedures one by one, so that you can thoroughly understand my thoughts, and I hope to help you.
author: Xiao Huang
Slow and firm growth
资源限制
时间限制：1.0s 内存限制：256.0MB
问题描述
给出一个字符串S，然后给出q条指令，分别有4种：
1. Append str
表示在S的最后追加一个字符串str。
例：
原字符串：ABCDE
执行 Append FGHIJ 后
字符串变为：ABCDEFGHIJ
2. Insert x str
表示在位置x处插入一个字符串str。（输入保证0<x<=当前字符串长度）
例：
原字符串：ABCGHIJ
执行 Insert 4 DEF 后
字符串变为：ABCDEFGHIJ
3. Swap a b c d
表示交换从第a位到第b位的字符串与从第c位到第d位的字符串。（输入保证0<a<b<c<d<=当前字符串长度）
例：
原字符串：ABGHIFCDEJ
执行 Swap 3 5 7 9后
字符串变为：ABCDEFGHIJ
4. Reverse a b
表示将从第a位到第b位的字符串反转。（输入保证0<a<b<=当前字符串长度）
例：
原字符串：ABGFEDCHIJ
执行 Reverse 3 7 后
字符串变为：ABCDEFGHIJ
最后输出按顺序执行完指令后的字符串。
输入格式
输入第一行包含字符串S，第二行包含一个整数q，接下来q行分别为q个指令。
输出格式
输出为1行，为按顺序执行完输入指令后的字符串。
样例输入
My
5
Append Hello
Insert 3 dlroW
Reverse 3 7
Swap 3 7 8 12
Swap 1 2 3 7
样例输出
HelloMyWorld
样例说明
原字符串：My
执行 Append Hello 后：MyHello
执行 Insert 3 dlroW 后：MydlroWHello
执行 Reverse 3 7 后：MyWorldHello
执行 Swap 3 7 8 12 后：MyHelloWorld
执行 Swap 1 2 3 7 后：HelloMyWorld
数据规模和约定
对于30%的数据，q=1；
对于70%的数据，如有Swap指令，Swap指令中b-a=d-c；
对于100%的数据，最终字符串长度不大于40000，1<=q<=150
Main function:
S is the input string, and I turn it into a list here because the list's own function is used in the Append () function and Insert () function. Of course, it is not necessary to turn it into a list, just modify the corresponding operation.
'' .jion (S) means to seamlessly convert the list into a character string.
Example: '' .jion (['1', '2', '3', '4', '5', '6']) will become 123456
n is the q in the title
if __name__ == "__main__":
S = list(input())
n = int(input())
if 1<=n<=150:
while n > 0:
nums = input()
S = fun(S,nums)
n -= 1
print(''.join(S))
About the Append function:
add s after the original S, here is the append () function using the list, and add the elements in s one by one after S, where the time complexity of append () is O (1).
def Append(S,s):
for i in s:
S.append(i)
About the Insert () function:
insert s at the x position of the original string S, and insert using the insert () function of the list.
def Insert(S,x,s):
for i in range(len(s)):
S.insert(x-1+i,s[i])
Regarding the Swap () function: It is
considered here that the different positions of d will have different effects on the slicing operation of the list, so it is divided into two cases of d = n and d <n.
def Swap(S,a,b,c,d):
n = len(S)
if n > d:
n1 = S[0:a-1]
n2 = S[a-1:b]
n3 = S[b:c-1]
n4 = S[c-1:d]
n5 = S[d:]
S = n1+n4+n3+n2+n5
elif n == d:
n1 = S[0:a-1]
n2 = S[a-1:b]
n3 = S[b:c-1]
n4 = S[c-1:]
S = n1+n4+n3+n2
return S
Reverse () function:
here we must consider the size of two values a and b, discuss the impact of the value of b on this function in the case of a = 1 and a ≠ 1, respectively. For example, when a = 1, b = n, then simply flip this function.
def Reverse(S,a,b):
n = len(S)
if a > 1:
if b < n:
n1 = S[:a-1]
n2 = S[a-1:b]
n3 = S[b:]
S = n1 + n2[::-1] +n3
elif b == n:
n1 = S[:a-1]
n2 = S[a-1:]
S = n1 + n2[::-1]
else:
if b < n:
n1 = S[:b]
n2 = S[b:]
s = n1[::-1] + n2
else:
S = S[::-1]
return S
Regarding the fun () function:
In this function, the value of each input is judged and the corresponding operation is performed.
def fun(S,nums):
a = nums.split()
if a[0] == 'Append':
Append(S,a[1])
elif a[0] == 'Insert':
Insert(S,int(a[1]),a[2])
elif a[0] == "Swap":
S = Swap(S,int(a[1]),int(a[2]),int(a[3]),int(a[4]))
elif a[0] == "Reverse":
S = Reverse(S,int(a[1]),int(a[2]))
return S
Finally, attach the detailed code:
def Append(S,s):
for i in s:
S.append(i)
def Insert(S,x,s):
for i in range(len(s)):
S.insert(x-1+i,s[i])
def Swap(S,a,b,c,d):
n = len(S)
if n > d:
n1 = S[0:a-1]
n2 = S[a-1:b]
n3 = S[b:c-1]
n4 = S[c-1:d]
n5 = S[d:]
S = n1+n4+n3+n2+n5
elif n == d:
n1 = S[0:a-1]
n2 = S[a-1:b]
n3 = S[b:c-1]
n4 = S[c-1:]
S = n1+n4+n3+n2
return S
def Reverse(S,a,b):
n = len(S)
if a > 1:
if b < n:
n1 = S[:a-1]
n2 = S[a-1:b]
n3 = S[b:]
S = n1 + n2[::-1] +n3
elif b == n:
n1 = S[:a-1]
n2 = S[a-1:]
S = n1 + n2[::-1]
else:
if b < n:
n1 = S[:b]
n2 = S[b:]
s = n1[::-1] + n2
else:
S = S[::-1]
return S
def fun(S,nums):
a = nums.split()
if a[0] == 'Append':
Append(S,a[1])
elif a[0] == 'Insert':
Insert(S,int(a[1]),a[2])
elif a[0] == "Swap":
S = Swap(S,int(a[1]),int(a[2]),int(a[3]),int(a[4]))
elif a[0] == "Reverse":
S = Reverse(S,int(a[1]),int(a[2]))
return S
if __name__ == "__main__":
S = list(input())
n = int(input())
if 1<=n<=150:
while n > 0:
nums = input()
S = fun(S,nums)
n -= 1
print(''.join(S))
