CodeForces 890B Vald and Cafes

Description：

Vlad likes to eat in cafes very much. During his life, he has visited cafes n times. Unfortunately, Vlad started to feel that his last visits are not any different from each other. To fix that Vlad had a small research.

First of all, Vlad assigned individual indices to all cafes. Then, he wrote down indices of cafes he visited in a row, in order of visiting them. Now, Vlad wants to find such a cafe that his last visit to that cafe was before his last visits to every other cafe. In other words, he wants to find such a cafe that he hasn't been there for as long as possible. Help Vlad to find that cafe.

Input

In first line there is one integer n (1 ≤ n ≤ 2·10⁵) — number of cafes indices written by Vlad.

In second line, n numbers a₁, a₂, ..., a_n (0 ≤ a_i ≤ 2·10⁵) are written — indices of cafes in order of being visited by Vlad. Vlad could visit some cafes more than once. Note that in numeration, some indices could be omitted.

Output

Print one integer — index of the cafe that Vlad hasn't visited for as long as possible.

Example

Input

5
1 3 2 1 2

Output

3

Input

6
2 1 2 2 4 1

Output

2

Note

In first test, there are three cafes, and the last visits to cafes with indices 1 and 2 were after the last visit to cafe with index 3; so this cafe is the answer.

In second test case, there are also three cafes, but with indices 1, 2 and 4. Cafes with indices 1 and 4 were visited after the last visit of cafe with index 2, so the answer is 2. Note that Vlad could omit some numbers while numerating the cafes.

题目大意：

假设某人去过n个咖啡馆（其中可能会有重复， 因为很喜欢咖啡馆所以他会在咖啡馆打标记。但是他想知道每一次拜访完所有的咖啡馆第一次去的是哪一个。 于是现在给你一个序列代表按时间顺序的咖啡馆标记， 输出他最后一次拜访完所有咖啡馆的第一个咖啡馆是哪个。

在这里举个例子：

比如

3 2 1 2 3

答案就是1， 一共标记过三个咖啡厅， 显然1 2 3去过了所有的咖啡厅里1是最前的。

解题思路：

设一个bool数组记录咖啡馆下标， cnt记录一共去过几个不同的咖啡馆。 从后向前遍历数组， 一旦发现遍历到当前下标的咖啡馆时恰好去过的不同的咖啡馆数 == cnt， 那么直接输出这个下标即可。

代码：

#include <iostream>
#include <sstream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <iomanip>
#include <utility>
#include <string>
#include <cmath>
#include <vector>
#include <bitset>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>

using namespace std;

/*
 *ios::sync_with_stdio(false);
 */

typedef long long ll;
typedef unsigned long long ull;
const int inf = 0x7fffffff;
const int mod = 1000000;
const int Max = (int) 2e5 + 9;

bool vis[Max];
int Rank[Max], arr[Max];

int main() {
    // definition
    int n, cnt = 0, temp = 0, ans;
    // initialization
    memset(vis, 0 ,sizeof(vis));
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        scanf("%d", &arr[i]);
        if (!vis[arr[i]]) {
            vis[arr[i]] = 1;
            cnt++;
        }
    }
    memset(vis, 0, sizeof(vis));
    for (int i = n - 1; i >= 0; --i) {
        if (!vis[arr[i]]) {
            temp++;
            ans = arr[i];
            vis[arr[i]] = 1;
        }
        // all the cafes
        if (temp == cnt) {
            printf("%d\n", ans);
            break;
        }
    }
    return 0;
}