feat: 添加P1775动态规划解法实现

实现Luogu P1775问题的动态规划解法，使用区间DP计算最小合并成本

src/10/P1775.cpp

@@ -0,0 +1,39 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+
+using ll = int64_t;
+
+const ll maxn = 300 + 5, inf = 1e18;
+
+ll m[maxn], s[maxn];
+ll n, dp[maxn][maxn];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin >> n;
+    for (ll i = 1; i <= n; ++i) {
+        std::cin >> m[i];
+        s[i] = s[i - 1] + m[i];
+        dp[i][i] = 0;
+    }
+
+    for (ll i = 1; i <= n; ++i) {
+        for (ll j = i + 1; j <= n; ++j) {
+            dp[i][j] = inf;
+        }
+    }
+
+    for (ll len = 2; len <= n; ++len) {
+        for (ll i = 1; i + len - 1 <= n; ++i) {
+            ll j = i + len - 1;
+            for (ll k = i; k < j; ++k) {
+                dp[i][j] = std::min(dp[i][j], dp[i][k] + dp[k + 1][j] + s[j] - s[i - 1]);
+            }
+        }
+    }
+
+    std::cout << dp[1][n] << "\n";
+}