状态转移表

 

type State int type CharType int  const (     STATE_INITIAL State = iota     STATE_INT_SIGN     STATE_INTEGER     STATE_POINT     STATE_POINT_WITHOUT_INT     STATE_FRACTION     STATE_EXP     STATE_EXP_SIGN     STATE_EXP_NUMBER     STATE_END )  const (     CHAR_NUMBER CharType = iota     CHAR_EXP     CHAR_POINT     CHAR_SIGN     CHAR_SPACE     CHAR_ILLEGAL )  func toCharType(ch byte) CharType {     switch ch {     case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':         return CHAR_NUMBER     case 'e', 'E':         return CHAR_EXP     case '.':         return CHAR_POINT     case '+', '-':         return CHAR_SIGN     case ' ':         return CHAR_SPACE     default:         return CHAR_ILLEGAL     } }  func isNumber(s string) bool {     transfer := map[State]map[CharType]State{         STATE_INITIAL: map[CharType]State{             CHAR_SPACE:  STATE_INITIAL,             CHAR_NUMBER: STATE_INTEGER,             CHAR_POINT:  STATE_POINT_WITHOUT_INT,             CHAR_SIGN:   STATE_INT_SIGN,         },         STATE_INT_SIGN: map[CharType]State{             CHAR_NUMBER: STATE_INTEGER,             CHAR_POINT:  STATE_POINT_WITHOUT_INT,         },         STATE_INTEGER: map[CharType]State{             CHAR_NUMBER: STATE_INTEGER,             CHAR_EXP:    STATE_EXP,             CHAR_POINT:  STATE_POINT,             CHAR_SPACE:  STATE_END,         },         STATE_POINT: map[CharType]State{             CHAR_NUMBER: STATE_FRACTION,             CHAR_EXP:    STATE_EXP,             CHAR_SPACE:  STATE_END,         },         STATE_POINT_WITHOUT_INT: map[CharType]State{             CHAR_NUMBER: STATE_FRACTION,         },         STATE_FRACTION: map[CharType]State{             CHAR_NUMBER: STATE_FRACTION,             CHAR_EXP:    STATE_EXP,             CHAR_SPACE:  STATE_END,         },         STATE_EXP: map[CharType]State{             CHAR_NUMBER: STATE_EXP_NUMBER,             CHAR_SIGN:   STATE_EXP_SIGN,         },         STATE_EXP_SIGN: map[CharType]State{             CHAR_NUMBER: STATE_EXP_NUMBER,         },         STATE_EXP_NUMBER: map[CharType]State{             CHAR_NUMBER: STATE_EXP_NUMBER,             CHAR_SPACE:  STATE_END,         },         STATE_END: map[CharType]State{             CHAR_SPACE: STATE_END,         },     }     state := STATE_INITIAL     for i := 0; i < len(s); i++ {         typ := toCharType(s[i])         if _, ok := transfer[state][typ]; !ok {             return false         } else {             state = transfer[state][typ]         }     }     return state == STATE_INTEGER || state == STATE_POINT || state == STATE_FRACTION || state == STATE_EXP_NUMBER || state == STATE_END } 

　　

作者：LeetCode-Solution
链接：https://leetcode-cn.com/problems/biao-shi-shu-zhi-de-zi-fu-chuan-lcof/solution/biao-shi-shu-zhi-de-zi-fu-chuan-by-leetcode-soluti/
来源：力扣（LeetCode）
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