Created
March 26, 2017 13:59
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#include <iostream> | |
#include <string> | |
#include <cstdio> | |
#include <cstring> | |
#include <vector> | |
#include <queue> | |
#include <cmath> | |
#include <map> | |
#include <set> | |
#include <algorithm> | |
#include <unordered_map> | |
#include <unordered_set> | |
using namespace std; | |
#define ff(i, n) for (int i = 0, END = (n); i < END; i ++) | |
#define fff(i, n, m) for (int i = (n), END = (m); i <= END; i ++) | |
#define dff(i, n, m) for (int i = (n), END = (m); i >= END; i --) | |
#define travel(e, first) for (int e = first, v = vv[first]; ~e; e = nxt[e], v = vv[e]) | |
#define clr(a, b) memset(a, b, sizeof(a)) | |
typedef long long ll; | |
int n; | |
const int N = 5e5, M = 55; | |
int dp[2][N + 5], goods[M]; | |
void input() { | |
ff(i, n) scanf("%d", goods + i); | |
} | |
int solve() { | |
clr(dp, -1); | |
int now = 0, pre = 1; | |
dp[now][0] = 0; | |
ff(i, n) { | |
int siz = goods[i]; | |
swap(now, pre); clr(dp[now], -1); | |
fff(v, 0, N) if (~dp[pre][v]) { | |
dp[now][v] = max(dp[now][v], dp[pre][v]); | |
if (v + siz <= N) { | |
dp[now][v + siz] = max(dp[now][v + siz], dp[pre][v]); | |
} | |
dp[now][abs(v - siz)] = max(dp[now][abs(v - siz)], dp[pre][v] + min(siz, v)); | |
} | |
} | |
return dp[now][0]; | |
} | |
int main() { | |
while (cin >> n) { | |
input(); | |
int ans = solve(); | |
printf("%d\n", ans == 0 ? -1 : ans); | |
} | |
} |
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