2017CCPC秦皇島ZOJ 3988 Prime Set
阿新 • • 發佈:2018-12-16
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <cmath>
#include <map>
#include <queue>
using namespace std;
#define N 2000010
#define inf 0x3f3f3f3f
int prime[N];
int num[3005];
vector<int>g[3005] ;
int dx[3005];
int dy[3005];
int dis;
int vis[3005];
int vm[3005];
int um[3005];
int n, k;
int f[3005];
int d[3005];
void init()
{
memset(num, 0, sizeof(num));
memset(g, 0, sizeof(g));
for (int i = 0; i < 3005; i++)
{
g[i].clear();
}
memset(vm, -1, sizeof(vm));
memset(um, -1, sizeof(um));
memset(f, -1, sizeof (f));
}
//模板
bool searchP()
{
queue<int>q;
dis = inf;
memset(dx, -1, sizeof(dx));
memset(dy, -1, sizeof(dy));
for (int i = 1; i <= n; i++)
if (um[i] == -1)
{
q.push(i);
dx[i] = 0;
}
while (!q.empty())
{
int u = q.front();
q.pop();
if (dx[u]>dis) break;
for (int i = 0; i<g[u].size(); i++)
{
int v = g[u][i];
if (dy[v] == -1)
{
dy[v] = dx[u] + 1;
if (vm[v] == -1) dis = dy[v];
else
{
dx[vm[v]] = dy[v] + 1;
q.push(vm[v]);
}
}
}
}
return dis != inf;
}
bool dfs(int u)
{
for (int i = 0; i<g[u].size(); i++)
{
int v = g[u][i];
if (!vis[v] && dy[v] == dx[u] + 1)
{
vis[v] = 1;
if (vm[v] != -1 && dy[v] == dis) continue;
if (vm[v] == -1 || dfs(vm[v]))
{
vm[v] = u;
um[u] = v;
return 1;
}
}
}
return 0;
}
int maxMatch()
{
int res = 0;
while (searchP())
{
memset(vis, 0, sizeof(vis));
for (int i = 1; i <= n; i++)
if (um[i] == -1 && dfs(i)) res++;
}
return res;
}
//素數打表
void isPrime()
{
memset(prime, 0, sizeof(prime));
prime[0] = prime[1] = 1;
for (int i = 2; i*i <= N; i++)
{
if (prime[i] == 0)
{
for (int j = i + i; j <= N; j += i)
{
prime[j] = 1;
}
}
}
return;
}
int main()
{
int cas;
scanf("%d", &cas);
isPrime();
while (cas--)
{
init();
int num_1 = 0;
int num_11 = 0;
scanf("%d%d", &n, &k);
for (int i = 1; i <= n; i++)
{
scanf("%d", &num[i]);
if (num[i] == 1)
{
num_1++;
}
}
//建圖
for (int i = 1; i <= n; i++)
{
for (int j = i + 1; j <= n; j++)
{
int t = num[i] + num[j];
if (num[i] == 1 && num[j] == 1)
{
continue;
}
if (prime[t] == 0)
{
if (num[i] % 2 == 0)
{
g[i].push_back(j);
}
else
{
g[j].push_back(i);
}
}
}
}
int ans = maxMatch();
int ans1 = 0;
int num_111 = 0;
memset(d, 0, sizeof(d));
//HK演算法中,um[i]==-1表示二分圖中的一側沒有匹配的點,vm[i]==-1表示另一側沒有匹配的點
for (int i = 1; i<=n; i++)
{
if (g[i].size() != 0)
{
if (um[i] == -1&&d[i]==0)
{
ans1++;
d[i]++;
if (num[i] == 1)
{
num_111++;//圖中不匹配1的個數
}
}
if (um[i] != -1 && num[i] == 1&&d[i]==0)
{
d[i]++;
num_11++; //圖中匹配點1的個數
}
for (int j = 0; j<g[i].size(); j++)
{
if (vm[g[i][j]] == -1&&d[g[i][j]]==0)
{
ans1++;
d[g[i][j]]++;
if (num[g[i][j]] == 1)
{
num_111++;
}
}
if (vm[g[i][j]] != -1 && num[g[i][j]] == 1&& d[g[i][j]] == 0)
{
num_11++;
d[g[i][j]]++;
}
}
}
}
//分一條邊的貢獻和一個點的共享兩種情況
int y = 0;
if (num_111+num_11 == 0)
{
y = num_1 / 2;
ans1 += num_1-(num_1/2*2);
}
else
{
y = num_111 / 2;
ans1 -= y * 2;
}
y = ans + y;
if (k <= y)
{
printf("%d\n", min(n,2*k));
}
else
{
printf("%d\n",2*y +min(ans1,(k-y)));
}
}
return 0;
}