123.买卖股票的最佳时机III

class Solution {public:int maxProfit(vector<int>& prices) {vector<int>dp(5, 0);dp[1] = -prices[0];dp[3] = -prices[0];for(int i=1; i<prices.size(); i++){if(prices[i]==prices[i-1]) continue;dp[1] = max(dp[1], -prices[i]);dp[2] = max(dp[2], dp[1]+prices[i]);dp[3] = max(dp[3], dp[2]-prices[i]);dp[4] = max(dp[4], dp[3]+prices[i]);}return dp[4];}};

188.买卖股票的最佳时机IV

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