#121 股票买卖(只允许交易一次求最大收益)

Author: Isaaclot

main/src/dynamic_programming/LC_121_BestTimeToBuyOrSellStock.java

@@ -8,7 +8,7 @@ public class LC_121_BestTimeToBuyOrSellStock {
     /**
      * 暴力遍历
      */
-    public int maxProfit(int[] prices) {
+    public int maxProfit_2d(int[] prices) {
         int maxProfit = 0;
         for (int i = 0; i < prices.length - 1; i++) {
             for (int j = i + 1; j < prices.length; j++) {
@@ -17,4 +17,17 @@ public int maxProfit(int[] prices) {
         }
         return maxProfit;
     }
+
+    public int maxProfit_1d(int[] prices) {
+        int min = Integer.MAX_VALUE;
+        int maxProfit = 0;
+        for (int price : prices) {
+            if (price > min) {
+                maxProfit = Math.max(maxProfit, price - min);
+            } else {
+                min = price;
+            }
+        }
+        return maxProfit;
+    }
 }

main/test/dynamic_programming/LC_121_BestTimeToBuyOrSellStockTest.java

@@ -11,8 +11,14 @@
  */
 public class LC_121_BestTimeToBuyOrSellStockTest {
     @Test
-    public void best_time_to_buy_sell_stock_test() {
+    public void best_time_to_buy_sell_stock_resolve_2D_test() {
         LC_121_BestTimeToBuyOrSellStock bt = new LC_121_BestTimeToBuyOrSellStock();
-        assertThat(bt.maxProfit(new int[]{7, 1, 5, 3, 6, 4}), is(5));
+        assertThat(bt.maxProfit_2d(new int[]{7, 1, 5, 3, 6, 4}), is(5));
+    }
+
+    @Test
+    public void best_time_to_buy_sell_stock_resolve_1D_test() {
+        LC_121_BestTimeToBuyOrSellStock bt = new LC_121_BestTimeToBuyOrSellStock();
+        assertThat(bt.maxProfit_1d(new int[]{7, 1, 5, 3, 6, 4}), is(5));
     }
 }