day34

买卖股票最佳时机

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

买卖股票最佳时机II

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

买卖股票最佳时机III

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