Update 0121.买卖股票的最佳时机.md

0121.买卖股票的最佳时机新增C语言实现

problems/0121.买卖股票的最佳时机.md

@@ -531,6 +531,52 @@ public class Solution
 }
 ```
 
+### C：
+
+> 贪心
+
+```c
+#define max(a, b) ((a) > (b) ? (a) : (b))
+#define min(a, b) ((a) > (b) ? (b) : (a))
+
+int maxProfit(int* prices, int pricesSize) {
+    int low = INT_MIN;
+    int result = 0;
+    for(int i = 0; i < pricesSize; i++){
+        low = min(low, prices[i]);
+        result = max(result, prices[i] - low);
+    }
+    return result;
+}
+```
+
+> 动态规划
+
+```c
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
+int maxProfit(int* prices, int pricesSize){
+    if(pricesSize == 0){
+        return 0;
+    }
+    // dp初始化
+    int ** dp = malloc(sizeof (int *) * pricesSize);
+    for(int i = 0; i < pricesSize; i++){
+        dp[i] = malloc(sizeof (int ) * 2);
+    }
+    // 下标0表示持有股票的情况下的最大现金，下标1表示不持有股票的情况下获得的最大现金
+    dp[0][0] = -prices[0];
+    dp[0][1] = 0;
+    for(int i = 1; i < pricesSize; i++){
+        dp[i][0] = max(dp[i - 1][0], - prices[i]);
+        dp[i][1] = max(dp[i - 1][1], dp[i - 1][0] + prices[i]);
+    }
+    return dp[pricesSize - 1][1];
+}
+```
+
+
+
 ### Rust:
 
 > 贪心
@@ -568,4 +614,3 @@ impl Solution {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
-