OJ-Problems-Source/HDOJ/4665_autoAC.cpp
2016-09-06 13:33:42 +08:00

83 lines
2.0 KiB
C++

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<vector>
#define MAXN 2010
using namespace std;
int arr[MAXN];
char str[MAXN];
bool flag;
int idx[MAXN];
int cnt[MAXN];
int st[2][MAXN];
int belong[MAXN];
int n;
vector<int> pos[MAXN];
void dfs(int x, int p1, int p2) {
if (x > n) {
flag = true;
}
if (flag) {
return;
}
if (p1 > 0 && p2 > 0
&& arr[st[0][min(p1, p2)]] != arr[st[1][min(p1, p2)]]) {
return;
}
if (belong[x] == 0) {
st[0][p1 + 1] = x;
dfs(x + 1, p1 + 1, p2);
} else if (belong[x] == 1) {
st[1][p2 + 1] = x;
dfs(x + 1, p1, p2 + 1);
} else {
st[0][p1 + 1] = x;
belong[pos[arr[x]][2]] = 1;
dfs(x + 1, p1 + 1, p2);
if (!flag) {
st[1][p2 + 1] = x;
belong[pos[arr[x]][2]] = 0;
dfs(x + 1, p1, p2 + 1);
belong[pos[arr[x]][2]] = -1;
}
}
}
int main() {
int T;
int i;
scanf("%d", &T);
while (T--) {
scanf("%d", &n);
memset(idx, 0, sizeof(idx));
memset(cnt, 0, sizeof(cnt));
for (i = 1; i <= n; i++) {
scanf("%d", &arr[i]);
cnt[arr[i]]++;
idx[i] = cnt[arr[i]];
pos[arr[i]].clear();
}
memset(belong, -1, sizeof(belong));
for (i = 1; i <= n; i++) {
if (idx[i] == 1) {
belong[i] = 0;
} else if (idx[i] == 2 && cnt[arr[i]] == 2) {
belong[i] = 1;
} else if (idx[i] == 4) {
belong[i] = 1;
}
pos[arr[i]].push_back(i);
}
flag = false;
dfs(1, 0, 0);
for (i = 1; i <= (n >> 1); i++) {
str[st[0][i]] = '0';
str[st[1][i]] = '1';
}
for (i = 1; i <= n; i++) {
putchar(str[i]);
}
putchar('\n');
}
return 0;
}