面试经典 150 题：121,125

121. 买卖股票的最佳时机

【参考代码】

动态规划解决

class Solution {
public:
    int maxProfit(vector<int>& prices) {
        int size = prices.size();
        int min_price = 99999, max_profit = 0;
        for(int i=0; i<size; i++){
            if(prices[i] < min_price){
                min_price = prices[i];
            }
            else if(prices[i] - min_price > max_profit){
                max_profit = prices[i] - min_price;
            }
        }
        return max_profit;
    }
};

125. 验证回文串

【参考代码】

class Solution {
public:
    bool isPalindrome(string s) {
        string s1 = "";
        int size = s.size();
        if(size == 0)
        {
            return true;
        }
        for(char c : s){
            if(isalnum(c)){
                s1 += tolower(c);
            }
        }
        string temp = s1;
        reverse(temp.begin(), temp.end());
        if(temp == s1)
        {
            return true;
        }
        else{
            return false;
        }
    }
};