leetcode 121. Best Time to Buy and Sell Stock 122.Best Time to Buy and Sell Stock II

 121

class Solution {
public:
int maxProfit(vector<int>& prices) {
int length = prices.size();
if(length <= 0)
return 0;
int min_num = 0x7FFFFFFF;
int max_sum = 0;
for(int i = 0;i < length;i++){
if(prices[i] < min_num)
min_num = prices[i];
if((prices[i] - min_num) > max_sum)
max_sum = prices[i] - min_num;
}
return max_sum;
}
};

122

class Solution {
public:
int maxProfit(vector<int>& prices) {
int length = prices.size();
if(length <= 0)
return 0;
int result = 0;
for(int i = 1;i < length;i++){
if(prices[i] - prices[i-1] > 0)
result += prices[i] - prices[i-1];
}
return result;
}
};

https://www.jianshu.com/p/34bbb0594bd9