feat: add C code in chapter_greedy (#755)

* add fractional_knapsack.c

* update CMakeLists

* add c code in chapter_greedy

* fix header format

* format code by clang-format

* remove extra comments

* replace ternary operator to MACRO

* parameters form adjustment

* Update fractional_knapsack.c

* Update max_capacity.c

* Update max_product_cutting.c

* add comments for consistency with cpp ver

* move MIN&MAX macro to source file

* typo fix

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/c/chapter_greedy/max_capacity.c

@@ -0,0 +1,43 @@
+/**
+ * File: max_capacity.c
+ * Created Time: 2023-09-15
+ * Author: xianii (xianyi.xia@outlook.com)
+ */
+
+#include "../utils/common.h"
+
+#define MIN(a, b) (a < b ? a : b)
+#define MAX(a, b) (a > b ? a : b)
+
+/* 最大容量：贪心 */
+int maxCapacity(int ht[], int htLength) {
+    // 初始化 i, j 分列数组两端
+    int i = 0;
+    int j = htLength - 1;
+    // 初始最大容量为 0
+    int res = 0;
+    // 循环贪心选择，直至两板相遇
+    while (i < j) {
+        // 更新最大容量
+        int capacity = MIN(ht[i], ht[j]) * (j - i);
+        res = MAX(res, capacity);
+        // 向内移动短板
+        if (ht[i] < ht[j]) {
+            i++;
+        } else {
+            j--;
+        }
+    }
+    return res;
+}
+
+/* Driver Code */
+int main(void) {
+    int ht[] = {3, 8, 5, 2, 7, 7, 3, 4};
+
+    // 贪心算法
+    int res = maxCapacity(ht, sizeof(ht) / sizeof(int));
+    printf("最大容量为 %d\n", res);
+
+    return 0;
+}