匈牙利算法（素数伴侣（HW1112））

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<vector>
#include<string>
#include<stdio.h>
#include<stdlib.h>
using namespace std;

const int N = 101;
bool isSushu(int n)
{
if (n % 2 == 0 || n % 3 == 0) return false;
else{
for (int i = 5; i*i <= n; i += 6)
if (n%i == 0 || n % (i + 2) == 0) return false;
return true;
}
}
int n1, n2, ans;
int result
;
bool state
;
bool map

;

bool find(int x)
{
for (int i = 1; i <= n2; ++i){
if (map[x][i] && !state[i]){
state[i] = true;
if (result[i] == 0 || find(result[i])){
result[i] = x;
return true;
}
}
}
return false;
}
int hungary()
{
for (int i = 1; i <= n1; ++i){
memset(state, 0, sizeof(state));
if (find(i)) ++ans;
}
return ans;
}

class xx{
string &name;
};
int main()
{
int n, val;
vector<int> odd, even;
scanf("%d", &n);
for (int i = 0; i < n; ++i){
scanf("%d", &val);
if (val % 2 == 0) even.push_back(val);
else odd.push_back(val);
}
memset(map, 0, sizeof(map));

for (int i = 0; i < odd.size(); ++i){
for (int j = 0; j < even.size(); ++j){
if (isSushu(odd[i] + even[j])) map[i + 1][j + 1] = true;
}
}

memset(result, 0, sizeof(result));
n1 = odd.size(); n2 = even.size(); ans = 0;
cout << hungary() << endl;
}