Add the section of max capacity problem. (#639)

codes/cpp/chapter_greedy/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_executable(coin_change_greedy coin_change_greedy.cpp)
-add_executable(fractional_knapsack fractional_knapsack.cpp)
+add_executable(fractional_knapsack fractional_knapsack.cpp)
+add_executable(max_capacity max_capacity.cpp)

codes/cpp/chapter_greedy/max_capacity.cpp

@@ -0,0 +1,39 @@
+/**
+ * File: max_capacity.cpp
+ * Created Time: 2023-07-21
+ * Author: Krahets (krahets@163.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* 最大容量：贪心 */
+int maxCapacity(vector<int> &ht) {
+    // 初始化 i, j 分列数组两端
+    int i = 0, j = ht.size() - 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 cap = min(ht[i], ht[j]) * (j - i);
+        res = max(res, cap);
+        // 向内移动短板
+        if (ht[i] < ht[j]) {
+            i++;
+        } else {
+            j--;
+        }
+    }
+    return res;
+}
+
+/* Driver Code */
+int main() {
+    vector<int> ht = {3, 8, 5, 2, 7, 7, 3, 4};
+
+    // 贪心算法
+    int res = maxCapacity(ht);
+    cout << "最大容量为 " << res << endl;
+
+    return 0;
+}