1210 - Sum of Consecutive Prime Numbers（数学水题）

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 12000;
int n,m,k,vis[maxn];
vector<int> prime;
void init() {
    memset(vis,0,sizeof(vis));
    int m = sqrt(11200+0.5);
    for(int i=2;i<=m;i++) if(!vis[i])
        for(int j=i*i;j<=11200;j+=i) vis[j] = 1;
    for(int i=2;i<=11200;i++) {
        if(!vis[i]) prime.push_back(i);
    }
}
int main() {
    init();
    while(~scanf("%d",&n)&&n) {
        int last = 0, rear = 0 , sum = prime[0], cnt = 0;
        while(last < prime.size()) {
            if(sum == n) cnt++, rear++, sum+=prime[rear];
            else if(sum < n) rear++, sum+=prime[rear];
            else sum-=prime[last++];
            if(last == rear && sum > n) break;
        }
        printf("%d\n",cnt);
    }
    return 0;
}