电子表格计算器 UVA - 215
A spreadsheet is a rectangular array of cells. Cells contain data or expressions that can be evaluated to
obtain data. A “simple” spreadsheet is one in which data are integers and expressions are mixed sums
and differences of integers and cell references. For any expression, if each cell that is referenced contains
an integer, then the expression can be replaced by the integer to which the expression evaluates. You
are to write a program which evaluates simple spreadsheets.
Input
Input consists of a sequence of simple spreadsheets. Each spreadsheet begins with a line specifying the
number of rows and the number of columns. No spreadsheet contains more than 20 rows or 10 columns.
Rows are labeled by capital letters A through T. Columns are labeled by decimal digits 0 through 9.
Therefore, the cell in the first row and first column is referenced as A0; the cell in the twentieth row
and fifth column is referenced as T4.
Following the specification of the number of rows and columns is one line of data for each cell,
presented in row-major order. (That is, all cells for the first row come first, followed by all cells for the
second row, etc.)
Each cell initially contains a signed integer value or an expression involving unsigned integer constants,
cell references, and the operators + (addition) and - (subtraction).
If a cell initially contains a signed integer, the corresponding input line will begin with an optional
minus sign followed by one or more decimal digits.
If a cell initially contains an expression, its input line will contain one or more cell references or
unsigned integer constants separated from each other by + and - signs. Such a line must begin with
a cell reference. No expression contains more than 75 characters. No line of input contains leading
blanks. No expression contains any embedded blanks. However, any line may contain trailing blanks.
The end of the sequence of spreadsheets is marked by a line specifying 0 rows and 0 columns.
Output
For each spreadsheet in the input, you are to determine the value of each expression and display
the resulting spreadsheet as a rectangular array of numbers with the rows and columns appropriately
labeled. In each display, all numbers for a column must appear right-justified and aligned with the
column label.
Operators are evaluated left to right in each expression; values in cells are always less than 10000
in absolute value. Since expressions may reference cells that themselves contain expressions, the order
in which cells are evaluated is dependent on the expressions themselves.
If one or more cells in a spreadsheet contain expressions with circular references, then the output
for that spreadsheet should contain only a list of the unevaluated cells in row-major order, one per line,
with each line containing the cell label, a colon, a blank, and the cell’s original expression.
A blank line should appear following the output for each spreadsheet.
Sample Input
2 2
A1+B1
5
3
B0-A1
3 2
A0
5
C1
7
A1+B1
B0+A1
0 0
Sample Output
0 1
A 3 5
B 3 -2
A0: A0
B0: C1
C1: B0+A1
意为给出表格，模拟表格计算表格的数值，如果能计算出结果，就输出表格的结果。如果不能，就输出无法计算的表格。
此题核心主要是一个递归。
其次也有无法输出的情况，也就是循环调用了表格，就会出现无法计算。
也有一个值得注意的地方比如，A0：A0-A0，这个就是无法计算的，而并不是0。
一开始因为有个取负的符号在，而且涉及到运算。所以才考虑用python，后来发现python似乎并不能简化此题，但是已经写了很多，也就那么写了下去。此间有很多还可以优化的地方，比如递归处代码冗余，其实可以写成函数，几个调用就成。
此题可能c语言会更好。
def init():
for i in range(a):
data[chr(ord('A')+i)]=[]
datas[chr(ord('A') + i)] = []
def dfs(char,j):
if j<b and datas[char][j]!=-999999:
return datas[char][j]
temp=data[char][j]
sum=0
start=0
end=len(temp)
while 1:
fh=temp.find('+',start,end)
if fh!=-1:
if temp[fh+1].isalpha():
if ord(temp[fh+1])>ord('A')+a-1:
return -999999
if fh+3<end and temp[fh+3].isdigit():
if temp[fh+1:fh+4] not in xh:
if int(temp[fh+2:fh+4])>=b:
return -999999
if datas[temp[fh + 1]][int(temp[fh+2:fh+4])]==-999999:
xh.append(temp[fh+1:fh+4])
else:
xh.clear()
return -999999
tempt=dfs(temp[fh+1],int(temp[fh+2:fh+4]))
if tempt==-999999:
return tempt
else:
sum+=tempt
start=fh+4
else:
if temp[fh+1:fh+3] not in xh :
if int(temp[fh+2])>=b:
return -999999
if datas[temp[fh + 1]][int(temp[fh+2])]==-999999:
xh.append(temp[fh+1:fh+3])
else:
xh.clear()
return -999999
tempt = dfs(temp[fh + 1], int(temp[fh+2]))
if tempt==-999999:
return tempt
else:
sum+=tempt
start=fh+3
else:
k=2
tsum=int(temp[fh+1])
while fh+k<end and temp[fh+k].isdigit():
tsum=tsum*10+int(temp[fh+k])
k=k+1
start=fh+k
sum=sum+tsum
else:
break
start = 0
end = len(temp)
while 1:
fh=temp.find('-',start,end)
if fh!=-1:
if temp[fh + 1].isalpha():
if ord(temp[fh+1])>ord('A')+a-1:
return -999999
if fh+3<end and temp[fh+3].isdigit():
if temp[fh+1:fh+4] not in xh :
if int(temp[fh+2:fh + 4])>=b:
return -999999
if datas[temp[fh + 1]][int(temp[fh+2:fh + 4])]==-999999:
xh.append(temp[fh+1:fh+4])
else:
xh.clear()
return -999999
tempt=dfs(temp[fh+1],int(temp[fh+2:fh+4]))
if tempt==-999999:
return tempt
else:
sum-=tempt
start=fh+4
else:
if temp[fh+1:fh+3] not in xh:
if int(temp[fh+2])>=b:
return -999999
if datas[temp[fh + 1]][int(temp[fh+2])]==-999999:
xh.append(temp[fh+1:fh+3])
else:
xh.clear()
return -999999
tempt = dfs(temp[fh + 1], int(temp[fh + 2]))
if tempt==-999999:
return tempt
else:
sum-=tempt
start=fh+3
elif temp[0]=='-':
sum-=int(temp[1:])
start=1
else:
k = 2
tsum = int(temp[fh + 1])
while fh+k<end and temp[fh + k].isdigit():
tsum = tsum * 10 + int(temp[fh + k])
k = k + 1
start=fh+k
sum = sum - tsum
else:
break
if temp[0].isalpha():
if ord(temp[fh + 1]) > ord('A') + a - 1:
return -999999
if len(temp)>2 and temp[2].isdigit():
if temp[:3] not in xh :
if int(temp[1:3])>=b:
return -999999
if datas[temp[0]][int(temp[1:3])]==-999999:
xh.append(temp[:3])
else:
return -999999
tempt=dfs(temp[0], int(temp[1:3]))
if tempt==-999999:
return tempt
else:
sum+=tempt
else:
if temp[:2] not in xh:
if int(temp[1])>=b:
return -999999
if datas[temp[0]][int(temp[1])]==-999999:
xh.append(temp[:2])
else:
return -999999
tempt=dfs(temp[0], int(temp[1]))
if tempt==-999999:
return tempt
else:
sum+=tempt
elif temp[0]!='-':
k = 1
tsum = int(temp[0])
while k<end and temp[k].isdigit():
tsum = tsum * 10 + int(temp[k])
k = k + 1
sum = sum + tsum
datas[char][j]=sum
for x in xh:
if datas[x[0]][int(x[1:])]!=-999999:
xh.remove(x)
return sum
if __name__=='__main__':
while 1:
a, b = map(int, input().split())
if a==0 and b==0:
break
data={}
datas = {}
init()
xh = []
f=1
# a,b=map(int,input().split())
for i in range(a):
for j in range(b):
s=input()
if s.isdigit() or (s[0]=='-' and s[1:].isdigit()):
datas[chr(ord('A')+i)].append(int(s))
else:
datas[chr(ord('A') + i)].append(-999999)
data[chr(ord('A')+i)].append(s)
for i in range(a):
for j in range(b):
if datas[chr(ord('A')+i)][j]==-999999:
if dfs(chr(ord('A')+i),j)==-999999:
f=0
if f:
print(' ',end='')
for j in range(b):
print('%6d'%(j),end='')
print()
for i in range(a):
print(chr(ord('A')+i),end='')
for j in range(b):
print('%6d'%(datas[chr(ord('A')+i)][j]),end='')
print()
else:
for i in range(a):
for j in range(b):
if datas[chr(ord('A') + i)][j] == -999999:
print(chr(ord('A')+i)+str(j)+': '+data[chr(ord('A')+i)][j])
print()