From 8f9fde289bc4f7c2948c9a6dcbb397eff8f31711 Mon Sep 17 00:00:00 2001
From: colorbox <colorbox222@gmail.com>
Date: Mon, 18 Mar 2024 00:22:19 +0900
Subject: [PATCH 1/2] Add solved codes for `121. Best Time to Buy and Sell
 Stock`

---
 121/1.cpp | 26 ++++++++++++++++++++++++++
 121/2.cpp | 18 ++++++++++++++++++
 121/3.cpp | 16 ++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 121/1.cpp
 create mode 100644 121/2.cpp
 create mode 100644 121/3.cpp

diff --git a/121/1.cpp b/121/1.cpp
new file mode 100644
index 0000000..05d1a7f
--- /dev/null
+++ b/121/1.cpp
@@ -0,0 +1,26 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        vector<int> minPricesFromStart;
+        vector<int> maxPricesFromEnd;
+
+        int minPrice = INT_MAX;
+        for(int i = 0; i < prices.size(); i++){
+            minPrice = min(minPrice, prices[i]);
+            minPricesFromStart.push_back(minPrice);
+        }
+        int maxPrice = -1;
+        for(int i = prices.size()-1; i >= 0; i--){
+            maxPrice = max(maxPrice, prices[i]);
+            maxPricesFromEnd.push_back(maxPrice);
+        }
+        reverse(maxPricesFromEnd.begin(), maxPricesFromEnd.end());
+
+        int maxProfit = 0;
+        for(int i = 0; i < prices.size(); i++){
+            int currentProfit = maxPricesFromEnd[i] - minPricesFromStart[i];
+            maxProfit = max(maxProfit, currentProfit);
+        }
+        return maxProfit;
+    }
+};
diff --git a/121/2.cpp b/121/2.cpp
new file mode 100644
index 0000000..79b34ef
--- /dev/null
+++ b/121/2.cpp
@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        int maxPrice = 0;
+        int minPrice = INT_MAX;
+        int maxProfit = 0;
+        for (int i = 0; i < prices.size(); i++) {
+            if (prices[i] < minPrice) {
+                minPrice = prices[i];
+            } else {
+                maxPrice = prices[i];
+                int currentProfit = maxPrice - minPrice;
+                maxProfit = max(maxProfit, currentProfit);
+            }
+        }
+        return maxProfit;
+    }
+};
diff --git a/121/3.cpp b/121/3.cpp
new file mode 100644
index 0000000..e2e117e
--- /dev/null
+++ b/121/3.cpp
@@ -0,0 +1,16 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        int minPrice = INT_MAX;
+        int maxProfit = 0;
+        for(int i = 0; i < prices.size(); i++) {
+            if (prices[i] < minPrice) {
+                minPrice = prices[i];
+            } else {
+                maxProfit = max(maxProfit, prices[i] - minPrice);
+            }
+        }
+
+        return maxProfit;
+    }
+};

From 72d4df2d8f6665dbafdf885d8b5522c2806931ae Mon Sep 17 00:00:00 2001
From: colorbox <colorbox222@gmail.com>
Date: Tue, 19 Mar 2024 01:44:14 +0900
Subject: [PATCH 2/2] =?UTF-8?q?=E3=83=AC=E3=83=93=E3=83=A5=E3=83=BC?=
 =?UTF-8?q?=E6=8C=87=E6=91=98=E3=82=92=E6=94=B9=E5=96=84=E3=81=97=E3=81=9F?=
 =?UTF-8?q?=E3=82=B3=E3=83=BC=E3=83=89=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 121/4.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 121/4.cpp

diff --git a/121/4.cpp b/121/4.cpp
new file mode 100644
index 0000000..885bf82
--- /dev/null
+++ b/121/4.cpp
@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        if(prices.empty())abort();
+        
+        int minPrice = prices[0];
+        int currentProfit = 0;
+        for(int price: prices) {
+            if (price < minPrice) {
+                minPrice = price;
+            } else {
+                currentProfit = max(currentProfit, price - minPrice);
+            }
+        }
+
+        return currentProfit;
+    }
+};