stock

Author: hitzzc

Diff for: README.md

@@ -107,6 +107,9 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [118. pascal's triangle](https://github.com/hitzzc/go-leetcode/tree/master/pascals_triangle)
 #### [119. pascal's triangle II](https://github.com/hitzzc/go-leetcode/tree/master/pascals_triangle_II)
 #### [120. triangle](https://github.com/hitzzc/go-leetcode/tree/master/triangle)
+#### [121. Best Time to Buy and Sell Stock](https://github.com/hitzzc/go-leetcode/tree/master/best_time_to_buy_and_sell_stock)
+#### [122. Best Time to Buy and Sell Stock II](https://github.com/hitzzc/go-leetcode/tree/master/best_time_to_buy_and_sell_stock_II)
+#### [123. Best Time to Buy and Sell Stock III](https://github.com/hitzzc/go-leetcode/tree/master/best_time_to_buy_and_sell_stock_III)
 #### [124. binary tree maximum path sum](https://github.com/hitzzc/go-leetcode/tree/master/binary_tree_maximum_path_sum)
 #### [125. valid palindrome](https://github.com/hitzzc/go-leetcode/tree/master/valid_palindrome)
 #### [126. word ladder II](https://github.com/hitzzc/go-leetcode/tree/master/word_ladder_II)
@@ -153,6 +156,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [174. Dungeon Game](https://github.com/hitzzc/go-leetcode/tree/master/dungeon_game)
 #### [179. Largest Number](https://github.com/hitzzc/go-leetcode/tree/master/largest_number)
 #### [187. Repeated DNA Sequences](https://github.com/hitzzc/go-leetcode/tree/master/repeated_dna_sequences)
+#### [188. Best Time to Buy and Sell Stock IV](https://github.com/hitzzc/go-leetcode/tree/master/best_time_to_buy_and_sell_stock_IV)
 #### [189. Rotate Array](https://github.com/hitzzc/go-leetcode/tree/master/rotate_array)
 #### [190. Reverse Bits](https://github.com/hitzzc/go-leetcode/tree/master/reverse_bits)
 #### [191. Number of 1 Bits](https://github.com/hitzzc/go-leetcode/tree/master/number_of_1bits)
@@ -221,6 +225,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [304. Range Sum Query 2D - Immutable](https://github.com/hitzzc/go-leetcode/tree/master/range_sum_query_immutable)
 #### [306. Additive Number](https://github.com/hitzzc/go-leetcode/tree/master/additive_number)
 #### [307. Range Sum Query - Mutable](https://github.com/hitzzc/go-leetcode/tree/master/range_sum_query_mutable)
+#### [309. Best Time to Buy and Sell Stock with Cooldown](https://github.com/hitzzc/go-leetcode/tree/master/best_time_to_buy_and_sell_stock_with_cooldown)
 
 
 

Diff for: best_time_to_buy_and_sell_stock/best_time_to_buy_and_sell_stock.cpp

@@ -0,0 +1,14 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        if (prices.size() == 0) return 0;
+        int min = prices[0];
+        int max = 0;
+        for (int i = 1; i < prices.size(); ++i) {
+        	int diff = prices[i] - min;
+        	if (diff > max) max = diff;
+        	if (prices[i] < min) min = prices[i];
+        }
+        return max;
+    }
+};

Diff for: best_time_to_buy_and_sell_stock_II/best_time_to_buy_and_sell_stock_II.cpp

@@ -0,0 +1,11 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+    	if (prices.size() == 0) return 0;
+   		int ret = 0;
+   		for (int i = 0; i < prices.size()-1; ++i) {
+   			if (prices[i+1] > prices[i]) ret += prices[i+1] - prices[i];
+   		}
+   		return ret;
+   	}
+};

Diff for: best_time_to_buy_and_sell_stock_III/best_time_to_buy_and_sell_stock_III.cpp

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        if (prices.size() == 0) return 0;
+        vector<int> fn1(prices.size(), 0);
+        vector<int> fn2(prices.size(), 0);
+        int minV = prices[0];
+        for (int i = 1; i < prices.size(); ++i) {
+        	fn1[i] = max(fn1[i-1], prices[i]-minV);
+        	minV = min(minV, prices[i]);
+        }
+        int maxV = prices[prices.size()-1];
+        for (int i = prices.size()-2; i >= 0; --i) {
+        	fn2[i] = max(fn2[i+1], maxV-prices[i]);
+        	maxV = max(maxV, prices[i]);
+        }
+        int ret = 0;
+        for (int i = 0; i < fn1.size(); ++i) {
+        	ret = max(ret, fn1[i] + fn2[i]);
+        }
+        return ret;
+    }
+};

Diff for: best_time_to_buy_and_sell_stock_IV/best_time_to_buy_and_sell_stock_IV.cpp

@@ -0,0 +1,24 @@
+class Solution {
+public:
+    int maxProfit(int k, vector<int>& prices) {
+        if (prices.size() < 2) return 0;
+        if (k > prices.size()/2) {
+            int ret = 0;
+            for (int i = 0; i < prices.size()-1; ++i) {
+                if (prices[i+1] - prices[i] > 0) ret += prices[i+1] - prices[i];
+            }
+            return ret;
+        }
+        vector<vector<int>> dp(k+1, vector<int>(prices.size()+1, 0));
+        for (int i = 1; i <= k; ++i) {
+            int maxV = dp[i-1][0] - prices[0];
+            for (int j = 1; j <= prices.size(); ++j) {
+                dp[i][j] = max(dp[i][j-1], maxV + prices[j-1]);
+                if (j < prices.size() && dp[i-1][j] - prices[j] > maxV) {
+                    maxV = dp[i-1][j] - prices[j];
+                }
+            }
+        }
+        return dp[k][prices.size()];
+    }
+};

Diff for: best_time_to_buy_and_sell_stock_with_cooldown/best_time_to_buy_and_sell_stock_with_cooldown.cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        if (prices.size() < 2) return 0;
+       	int buy = -prices[0];
+       	int sell = -1;
+       	int cold = 0;
+       	int tmp;
+       	for (int i = 1; i < prices.size(); ++i) {
+       		tmp = buy;
+       		buy = max(tmp, cold-prices[i]);
+       		cold = max(cold, sell);
+       		sell = tmp+prices[i];
+       	}
+       	return max(sell, cold);
+    }
+};