Tue, 29 Jan 2019 17:06:58 +0800

C279991/.tutorial.md

@@ -17,3 +17,9 @@
 ## C - Sockets
 
 将电脑（连同id）一起扔进multimap里，然后对socket排序，从最小的开始（这是个什么神奇道理）检查是否有符合的电脑，如果没有就`(x+1)/2`，直到找到这样的电脑或比当前最小电脑所用量还小（其实直接循环个31次应该也能过）。
+
+### 
+
+## D - Bipartite Graph
+
+首先已知这是一个二分图，将其染色并统计两部分数量。将孤立的点选择加到集合一还是二，取最大值即可，时间复杂度与输入复杂度相同。

C279991/CMakeLists.txt

@@ -1,7 +1,8 @@
 cmake_minimum_required(VERSION 3.10) 
-set(CMAKE_CXX_STANDARD 17) 
 set(CMAKE_CXX_FLAGS "/Zc:__cplusplus") 
+set(CMAKE_CXX_STANDARD 17) 
 include_directories("D:\\PortableApps\\MSYS2\\mingw64\\include\\c++\\8.2.1\\x86_64-w64-mingw32") 
 add_executable("A" "A.cpp") 
 add_executable("B" "B.cpp") 
 add_executable("C" "C.cpp") 
+add_executable("D" "D.cpp") 

C279991/D.cpp

@@ -0,0 +1,46 @@
+#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
+#include <bits/stdc++.h>
+using namespace std;
+const int N = 10010, M = 100010;
+int adj[N], nxt[M << 1], to[M << 1], ecnt, col[N];
+inline void addEdge(int f, int t)
+{
+    ecnt++;
+    nxt[ecnt] = adj[f];
+    adj[f] = ecnt;
+    to[ecnt] = t;
+}
+void dfs(int x)
+{
+    for (int e = adj[x], t; e; e = nxt[e])
+        if (t = to[e], !col[to[e]])
+        {
+            col[t] = 3 - col[x];
+            dfs(t);
+        }
+}
+int main()
+{
+    int T;
+    scanf("%d", &T);
+    while (T--)
+    {
+        memset(adj, 0, sizeof(adj)), ecnt = 0;
+        memset(col, 0, sizeof(col));
+        int n, m, u, v;
+        scanf("%d%d", &n, &m);
+        for (int i = 0; i < m; i++)
+            scanf("%d%d", &u, &v), addEdge(u, v), addEdge(v, u);
+        if (m == 0) u = 1;
+        col[u] = 1;
+        dfs(u);
+        int cnt[] = {0, 0, 0};
+        for (int i = 1; i <= n; i++)
+            cnt[col[i]]++;
+        int ans = 0;
+        for (int i = 0; i <= cnt[0]; i++)
+            ans = max(ans, (cnt[1] + i) * (cnt[2] + cnt[0] - i));
+        printf("%d\n", ans - m);
+    }
+    return 0;
+}