Valid Number

Borrow the solution from here: Use DFA to solve the problem.
http://discuss.leetcode.com/questions/241/valid-number

class Solution {
public:
    enum token {
        space,
        digit,
        sign,
        dot,
        exp,
        invalid
    };
    
    bool isNumber(const char *s) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int table[][6] = {
            {0, 1, 2, 3, -1, -1},
            {8, 1, -1, 4, 5, -1}, 
            {-1, 1, -1, 3, -1, -1}, 
            {-1, 4, -1, -1, -1, -1},
            {8, 4, -1, -1, 5, -1},
            {-1, 7, 6, -1, -1, -1},
            {-1, 7, -1, -1, -1, -1},
            {8, 7, -1, -1, -1, -1},
            {8, -1, -1, -1, -1, -1}
        };
        token curr_token;
        int curr_state = 0;
        while (*s != '\0') {
            curr_token = invalid;
            if (isdigit (*s))
                curr_token = digit;
            if (isspace (*s))
                curr_token = space;
            if (*s=='+' || *s=='-')
                curr_token = sign;
            if (*s == '.')
                curr_token = dot;
            if (*s=='e' || *s=='E')
                curr_token = exp;
            curr_state = table[curr_state][curr_token];
            if (curr_state == -1)
                return false;
            s++;
        }
        return (curr_state==1 || curr_state==4 || curr_state==7 || curr_state==8);
    }
};

Implement strStr

class Solution {
public:
    char *strStr(char *haystack, char *needle) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        int len_h = strlen(haystack);
        int len_n = strlen(needle);
        if (len_h < len_n)
            return NULL;
        if (len_n == 0)
            return haystack;
        
        char *p_h = haystack, *p_n = needle;
        while (p_h <= haystack+len_h-len_n) {
            if (*p_h != *p_n) {
                p_h++;
            }
            else {
                int i;
                for (i = 0; i < len_n; i++) {
                    if (*(p_h+i) != *(p_n+i))
                        break;
                }
                if (i == len_n)
                    return p_h;
                else
                    p_h++;
            }
        }
        return NULL;
    }
};

Install numpy and scipy on Mac

Found a useful link about how to install numpy and scipy on mac.

https://github.com/fonnesbeck/ScipySuperpack