update: 0, 3, 4

0-杂项.md

@@ -144,4 +144,46 @@ int main()
 
     return 0;
 }
+```
+
+## 三分
+
+```cpp
+double cal()
+{
+    double l = 0, r = 1e10;
+    for (int i = 1; i <= 100; i++)
+    {
+        double m1 = l + (r - l) / 3;
+        double m2 = (r - l) / 3 * 2 + l;
+        if (f(m1) < f(m2))
+            l = m1;
+        else
+            r = m2;
+    } // 求最大值
+    return f(l);
+}
+
+int cal()
+{
+    int l = 0, r = 1e10;
+    while (l + 2 < r)
+    {
+        int m1 = l + (r - l) / 3;
+        int m2 = (r - l) / 3 * 2 + l;
+        if (f(m1) < f(m2))
+        {
+            l = m1;
+        }
+        else
+        {
+            r = m2;
+        }
+    }
+    int ans = f(l);
+    for (int i = l + 1; i <= r; i++)
+    {
+        ans = max(ans, f(i));
+    }
+}
 ```

3-动态规划.md

@@ -188,3 +188,17 @@ int main()
 }
 ```
 
+## 状压DP解哈密顿回路问题
+
+```cpp
+
+int dp[(1 << 21)][20];
+
+for (int i = 0; i < (1 << (n + 1)); i++)
+            for (int j = 1; j <= n; j++)
+                if (dp[i][j])
+                    for (int k = 1; k <= n; k++)
+                        if (a[j][k] && (((i >> k) & 1) == 0))
+                            dp[i | (1 << k)][k] = 1;
+
+```