Project Euler：Problem 77 Prime summations

It is possible to write ten as the sum of primes in exactly five different ways:

7 + 3

5 + 5

5 + 3 + 2

3 + 3 + 2 + 2

2 + 2 + 2 + 2 + 2

What is the first value which can be written as the sum of primes in over five thousand different ways?

#include <iostream>
#include <string>
using namespace std;

int prime[1000];  //存储前1000个质数
bool vis[10000];

void getPrime()
{
int count = 0;
memset(vis, 0, sizeof(vis));
for (int i = 2; i < 10000; i++)
{
if (!vis[i])
{
if (count >= 1000)
break;
prime[count++] = i;
for (int j = i*i; j < 10000; j += i)
vis[j] = 1;
}
}
}
int main()
{
getPrime();
int *ways;
int num = 2;
while (true)
{

ways = new int[num+1];
for (int i = 0; i < num + 1; i++)
ways[i] = 0;
ways[0] = 1;
for (int i = 0; i < 1000; i++)
{
for (int j = prime[i]; j <= num; j++)
{
ways[j] += ways[j - prime[i]];
}
}
//cout << num <<" " << ways[num]<< endl;
if (ways[num]>5000)
break;
else
num++;
}
cout << num << endl;

system("pause");
return 0;
}