leetcode 65. Valid Number

本文给出一种可以AC的Valid Number的定义，算法的有限状态机及源码。

1 Valid Number的定义(参考浮点数语法)：

Name	Regular Expression
space	' ' \| '\t'
sign	[+-]
digit	[0-9]+
exp	'e'
dot	'.'
seq (digit sequence)	digit+
exponent	exp sign? seq
significand	seq seq dot seq dot seq dot seq
valid_number	space* sign? significand exponent? space*

2 算法的有限状态机

3 源码

#include <stdbool.h>#ifndef SYMBOL_CASE
#define SYMBOL_CASE(symbol) case symbol:
#endif#ifndef SPACE_CASE
#define SPACE_CASE \SYMBOL_CASE(' ') \SYMBOL_CASE('\t')
#endif#ifndef DIGIT_CASE
#define DIGIT_CASE \SYMBOL_CASE('0') \SYMBOL_CASE('1') \SYMBOL_CASE('2') \SYMBOL_CASE('3') \SYMBOL_CASE('4') \SYMBOL_CASE('5') \SYMBOL_CASE('6') \SYMBOL_CASE('7') \SYMBOL_CASE('8') \SYMBOL_CASE('9')
#endif#ifndef SIGN_CASE
#define SIGN_CASE  \SYMBOL_CASE('+') \SYMBOL_CASE('-')
#endif#ifndef DOT_CASE
#define DOT_CASE  \SYMBOL_CASE('.')
#endif#ifndef EXP_CASE
#define EXP_CASE  \SYMBOL_CASE('e')
#endif#ifndef FINAL_CASE
#define FINAL_CASE  \SYMBOL_CASE('\0')
#endif#ifndef STATUS_SUCCESS
#define STATUS_SUCCESS 16
#endif#ifndef STATUS_FAILURE
#define STATUS_FAILURE -1
#endif#ifndef DEFINE_NEXT_STATUS_FUNC_HEAD
#define DEFINE_NEXT_STATUS_FUNC_HEAD(num)          \int next_status_##num(char c)                  \{                                              \int status = STATUS_FAILURE;               \\switch (c)
#endif#ifndef DEFINE_NEXT_STATUS_FUNC_TAIL
#define DEFINE_NEXT_STATUS_FUNC_TAIL               \return status;                                 \
}
#endif#ifndef INVOKE_NEXT_STATUS_FUNC
#define INVOKE_NEXT_STATUS_FUNC(num)               \case num:                                      \status = next_status_##num(c);                 \break;
#endif#ifndef PROCESS_CASE
#define PROCESS_CASE(case_statement, status_code)  \case_statement                                 \status = status_code;                          \break;
#endif#ifndef PROCESS_CASE_DEFAULT
#define PROCESS_CASE_DEFAULT                       \default:                                       \break;
#endifDEFINE_NEXT_STATUS_FUNC_HEAD(0)
{PROCESS_CASE(SPACE_CASE, 0)PROCESS_CASE(SIGN_CASE, 1)PROCESS_CASE(DIGIT_CASE, 2)PROCESS_CASE(DOT_CASE, 3)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(1)
{PROCESS_CASE(DIGIT_CASE, 2)PROCESS_CASE(DOT_CASE, 3)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(2)
{PROCESS_CASE(DIGIT_CASE, 2)PROCESS_CASE(DOT_CASE, 4)PROCESS_CASE(EXP_CASE, 5)PROCESS_CASE(SPACE_CASE, 8)PROCESS_CASE(FINAL_CASE, STATUS_SUCCESS)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(3)
{PROCESS_CASE(DIGIT_CASE, 4)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(4)
{PROCESS_CASE(DIGIT_CASE, 4)PROCESS_CASE(EXP_CASE, 5)PROCESS_CASE(SPACE_CASE, 8)PROCESS_CASE(FINAL_CASE, STATUS_SUCCESS)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(5)
{PROCESS_CASE(SIGN_CASE, 6)PROCESS_CASE(DIGIT_CASE, 7)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(6)
{PROCESS_CASE(DIGIT_CASE, 7)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(7)
{PROCESS_CASE(DIGIT_CASE, 7)PROCESS_CASE(SPACE_CASE, 8)PROCESS_CASE(FINAL_CASE, STATUS_SUCCESS)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILDEFINE_NEXT_STATUS_FUNC_HEAD(8)
{PROCESS_CASE(SPACE_CASE, 8)PROCESS_CASE(FINAL_CASE, STATUS_SUCCESS)PROCESS_CASE_DEFAULT
}
DEFINE_NEXT_STATUS_FUNC_TAILbool isNumber(char* s) {int status = 0;char c;while (status != STATUS_FAILURE && status != STATUS_SUCCESS){c = *(s++);switch (status){INVOKE_NEXT_STATUS_FUNC(0)INVOKE_NEXT_STATUS_FUNC(1)INVOKE_NEXT_STATUS_FUNC(2)INVOKE_NEXT_STATUS_FUNC(3)INVOKE_NEXT_STATUS_FUNC(4)INVOKE_NEXT_STATUS_FUNC(5)INVOKE_NEXT_STATUS_FUNC(6)INVOKE_NEXT_STATUS_FUNC(7)INVOKE_NEXT_STATUS_FUNC(8)default:break;}}return status == STATUS_SUCCESS;
}

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