feat: 2025-10-31打卡

121.best-time-to-buy-and-sell-stock.java

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+/*
+ * @lc app=leetcode id=121 lang=java
+ *
+ * [121] Best Time to Buy and Sell Stock
+ */
+
+// @lc code=start
+class Solution {
+    public int maxProfit(int[] prices) {
+        if(prices == null || prices.length == 0) {
+            return 0;
+        }   
+        int min = prices[0], profit = 0;
+        for(int i=1; i<prices.length; i++) {
+            profit = Math.max(profit, prices[i] - min);
+            min = Math.min(min, prices[i]);
+        }
+        return profit;
+    }
+}
+// @lc code=end
+