Solve a given equation and return the value of x in the form of string "x=#value". The equation contains only '+', '-' operation, the variable x and its coefficient.
If there is no solution for the equation, return "No solution".
If there are infinite solutions for the equation, return "Infinite solutions".
If there is exactly one solution for the equation, we ensure that the value of x is an integer.
Example 1:
Input: "x+5-3+x=6+x-2"
Output: "x=2"
Example 2:
Input: "x=x"
Output: "Infinite solutions"
Example 3:
Input: "2x=x"
Output: "x=0"
Example 4:
Input: "2x+3x-6x=x+2"
Output: "x=-1"
Example 5:
Input: "x=x+2"
Output: "No solution"
Python Solution:
class Solution(object):
def solveEquation(self, equation):
"""
:type equation: str
:rtype: str
"""
l = re.split('([=+-])', equation)
x = 0
res = 0
op = 1
sign = 1
for val in l:
if not val: continue
if val == '+':
op = 1
elif val == '-':
op = -1
elif val == '=':
op = 1
sign = -1
elif val[-1] == 'x':
val = int(val[:-1]) if val[:-1] else 1
x += val * op * sign
op = 1
else:
res += int(val) * op * sign
if x == 0:
if res == 0:
return "Infinite solutions"
else:
return "No solution"
return 'x={}'.format(-res // x)
Summary:
- It's not complex.
LeetCode: 640. Solve the Equation
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