diff --git "a/leetcode3/\355\231\251\354\235\200\354\247\200/121. Best Time to Buy and Sell Stock.js" "b/leetcode3/\355\231\251\354\235\200\354\247\200/121. Best Time to Buy and Sell Stock.js"
new file mode 100644
index 00000000..afbf84c9
--- /dev/null
+++ "b/leetcode3/\355\231\251\354\235\200\354\247\200/121. Best Time to Buy and Sell Stock.js"	
@@ -0,0 +1,14 @@
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+var maxProfit = function(prices) {
+    let max=0;
+    let maxProfit=0;
+    for(let i=prices.length-1;i>=0;i--){
+        max=Math.max(max,prices[i]);
+        maxProfit=Math.max(maxProfit,max-prices[i]);
+    }
+
+    return maxProfit;
+};
\ No newline at end of file