#include <cstdio>
#include <algorithm>
#include <ctime>
#include <set>

using namespace std;
int a[11], b[11], c[11];
int main(){
    // 檔案對比
    /*while (1){
        if (system("fc print1.txt print2.txt")) break;
    }*/
    // 隨機數
    /*srand(time(0));
    int n = rand() % 10000;
    printf("%d\n", n);*/
    // 讀寫
    /*freopen("csp2021.in", "r", stdin);
    freopen("csp2021.out", "w", stdout);*/
    // 離散化
    /*a[1] = 10, a[2] = 9, a[3] = 15, a[4] = 1, a[5] = 15;
    c[1] = 10, c[2] = 9, c[3] = 15, c[4] = 1, a[5] = 15;
    sort(a + 1, a + 5 + 1);
    int len = unique(a + 1, a + 5 + 1) - a - 1;
    for (int i = 1; i <= len; ++i)
        b[i] = lower_bound(a + 1, a + len + 1, c[i]) - a;
    for (int i = 1; i <= len; ++i)
        printf("%d ", b[i]);
    // 3 2 4 1 */
    // set (不可重複) multiset (可重複)
    // 插入 -> insert 刪除 -> erase
    set<int> s1;
    // 0 1 2 3 4 5
    s1.insert(10), s1.insert(5), s1.insert(77), 
    s1.insert(7), s1.insert(8), s1.insert(7777777);
    s1.erase(5);
    printf("%d\n", *s1.find(777));
    printf("%d\n", *s1.lower_bound(8));// >= x 的最小的一個
    printf("%d\n", *s1.end());
    printf("%d\n", *s1.upper_bound(4));// > x 的最小的一個
    // next_permutation
    /*for (int i = 1; i <= 4; ++i) a[i] = i;
    do {                                                                    
        for (int i = 1; i <= 4; ++i) printf("%d ", a[i]);
        puts("");
    } while (next_permutation(a + 1, a + 5));*/
    return 0;
}