AtCoder Grand Contest 020 C - Median Sum

#pragma warning(disable:4996)
#include<bitset>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define ll long long

#define lson root<<1
#define rson root<<1|1
#define mid (l+r)>>1

#define mem(arr, in) memset(arr, in, sizeof(arr))
using namespace std;

const int maxn = 4000005;

int n;
bitset<maxn> bs;

int main()
{
    while (cin >> n) {
        int res = 0;

        bs[0] = 1;
        for (int i = 1; i <= n; i++) {
            int tp;
            cin >> tp;
            res += tp;
            bs |= bs << tp;
        }

        int m = (res + 1) / 2;
        for (int i = m; i <= res; i++) if (bs[i]) {
            printf("%d\n", i);
            break;
        }
    }
    return 0;
}