commit

Author: 王俊超

Diff for: 【122】【Best Time to Buy and Sell Stock II】/src/Solution.java

@@ -0,0 +1,37 @@
+/**
+ * @author: wangjunchao(王俊超)
+ * @time: 2018-10-09 08:46
+ **/
+public class Solution {
+    public int maxProfit(int[] prices) {
+
+        if (prices == null || prices.length < 2) {
+            return 0;
+        }
+
+        int buy = 0;
+        int sell = 1;
+
+        int sum = 0;
+        while (sell < prices.length) {
+            // 从buy的位置开始找降序子序列中最小的值
+            while (buy + 1 < prices.length && prices[buy] >= prices[buy + 1]) {
+                buy++;
+            }
+            // 从buy的位置开始找升序子序列中最大的值
+            sell = buy + 1;
+            while (sell + 1 < prices.length && prices[sell] <= prices[sell + 1]) {
+                sell++;
+            }
+
+            if (sell < prices.length) {
+                sum += prices[sell] - prices[buy];
+            }
+
+            buy = sell + 1;
+
+        }
+
+        return sum;
+    }
+}

Diff for: 【122】【Best Time to Buy and Sell Stock II】/src/Test.java

@@ -0,0 +1,18 @@
+/**
+ * @author: wangjunchao(王俊超)
+ * @time: 2018-10-09 09:13
+ **/
+public class Test {
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+
+        int[] prices = {7, 1, 5, 3, 6, 4};
+        System.out.println(solution.maxProfit(prices) == 7);
+
+        int[] prices2 = {1, 2, 3, 4, 5};
+        System.out.println(solution.maxProfit(prices2) == 4);
+
+        int[] prices3 = {7, 6, 4, 3, 1};
+        System.out.println(solution.maxProfit(prices3) == 0);
+    }
+}