class Solution {
public:/*dp[i][0]第i天持有股票所得的最大现金；dp[i][1]第i天不持有股票所得的最大现金；dp[i][0] = max(dp[i-1][0], - prices[i]);dp[i][1] = max(dp[i-1][1], dp[i-1][0] + prices[i]);*/int maxProfit(vector<int>& prices) {int len = prices.size();vector<vector<int>> dp(len, vector<int>(2, 0));dp[0][0] = - prices[0];dp[0][1] = 0;for(int i = 1; i < len; i++){dp[i][0] = max(dp[i-1][0], - prices[i]);dp[i][1] = max(dp[i-1][1], dp[i-1][0] + prices[i]);}return dp[len-1][1];}
};

class Solution {
public:/*dp[i]为第i天的最大利润；dp[i] = max(dp[i - 1], dp[i - 1] + prices[i] - prices[i - 1]);*/int maxProfit(vector<int>& prices) {int size = prices.size();vector<int> dp(size);dp[0] = 0;for(int i = 1; i < size; i++){dp[i] = max(dp[i - 1], dp[i - 1] + prices[i] - prices[i - 1]);}return dp[size - 1];}
};

class Solution {
public:int maxProfit(vector<int>& prices) {int size = prices.size();vector<vector<int>> dp(size, vector<int>(2));dp[0][0] = - prices[0];dp[0][1] = 0;for(int i = 1; i < size; i++){dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] - prices[i]);dp[i][1] = max(dp[i - 1][1], dp[i - 1][0] + prices[i]);}return dp[size - 1][1];}
};