LeetCode: Best Time to Buy and Sell Stock III

思路对的，但是没弄好code，改了挺多，最后还是runtime exceed了，看了网上答案再把自己的code改了改

class Solution {
public:
    int maxProfit(vector<int> &prices) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (prices.size() <= 1) return 0;
        int size = prices.size();
        vector<int> left(size);
        vector<int> right(size);
        int minprice = prices[0];
        left[0] = 0;
        for (int i = 1; i < size; i++) {
            minprice = min(minprice, prices[i]);
            left[i] = max(left[i-1], prices[i]-minprice);
        }
        int maxprice = prices[size-1];
        right[size-1] = 0;
        for (int i = size-2; i >= 0; i--) {
            maxprice = max(maxprice, prices[i]);
            right[i] = max(right[i+1], maxprice - prices[i]);
        }
        int maxprofit = 0;
        for (int i = 0; i < size; i++) {
             maxprofit = max(maxprofit, left[i]+right[i]);
        }
        return maxprofit;
    }
};

 C#:

public class Solution {
    public int MaxProfit(int[] prices) {
        int size = prices.Count();
        if (size < 1) return 0;
        int[] leftProfit = new int[size];
        int[] rightProfit = new int[size];
        int leftMinPrice = prices[0];
        int rightMaxPrice = prices[size-1];
        leftProfit[0] = 0;
        rightProfit[size-1] = 0;
        for (int i = 1; i < prices.Count(); i++) {
            leftProfit[i] = Math.Max(leftProfit[i-1], prices[i] - leftMinPrice);
            leftMinPrice = Math.Min(leftMinPrice, prices[i]);
        }
        for (int i = size-2; i >= 0; i--) {
            rightProfit[i] = Math.Max(rightProfit[i+1], rightMaxPrice - prices[i]);
            rightMaxPrice = Math.Max(rightMaxPrice, prices[i]);
        }
        int maxProfit = 0;
        for (int i = 0; i < size; i++) maxProfit = Math.Max(maxProfit, leftProfit[i] + rightProfit[i]);
        return maxProfit;
    }
}

 java

public class Solution {
    public int maxProfit(int[] prices) {
        if (prices.length < 2) return 0;
        int[] leftProfit = new int[prices.length];
        int[] rightProfit = new int[prices.length];
        int minPrice = prices[0];
        leftProfit[0] = 0;
        for (int i = 1; i < prices.length; i++)
        {
            leftProfit[i] = Math.max(leftProfit[i-1], prices[i] - minPrice);
            minPrice = Math.min(minPrice, prices[i]);
        }
        int len = prices.length;
        int maxPrice = prices[len - 1];
        rightProfit[len - 1] = 0;
        for (int i = prices.length - 2; i >= 0; i--)
        {
            rightProfit[i] = Math.max(rightProfit[i+1], maxPrice - prices[i]);
            maxPrice = Math.max(maxPrice, prices[i]);
        }
        int ans = 0;
        for (int i = 0; i < len; i++)
        {
            ans = Math.max(ans, leftProfit[i] + rightProfit[i]);
        }
        return ans;
    }
}