C++ 解法, 执行用时: 17ms, 内存消耗: 1400KB, 提交时间: 2020-12-22

#include<cstdio>
#include<cstring>
bool v[200010];
int a[100010];
int main()
{
    memset(v,0,sizeof(v));
    int n,m;scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d",&a[i]);
         
    }
    for(int i=m;i>0;i--)
    if(!v[a[i]])printf("%d\n",a[i]),v[a[i]]=1;
    for(int i=1;i<=n;i++)
        if(!v[i]){printf("%d\n",i);v[i]=1;}
    return 0;
}

C++ 解法, 执行用时: 17ms, 内存消耗: 1548KB, 提交时间: 2022-04-23

#define _CRT_SECURE_NO_WARNINGS
#define DEBUG123
#ifdef DEBUG
#include "goodhead.h"
#endif // DEBUG
#ifndef DEBUG
#include <bits/stdc++.h>
#endif // !DEBUG
using namespace std;
///Quoted from 912SCL template
#define MAXN 2000005
#define INF 1000000007                                
#define _for(i, a, b) for (int i = (a); i < (b); ++i)
#define _rep(i, a, b) for (int i = (a); i <= (b); ++i)
typedef long long ll;
typedef pair<string, string> pss;
typedef pair<int, int> pii;
typedef pair<string, int> psi;
const double PI = acos(-1.0);
const double eps = 1e-6;
const int MOD = 1e7 + 7;
inline int read()
{
    int x = 0, w = 1;
    char ch = 0;
    while (ch < '0' || ch > '9')
    { // ch 不是数字时
        if (ch == '-')
            w = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = x * 10 + (ch - '0');
        ch = getchar();
    }
    return x * w;
}
inline void write(int x)
{
    static int sta[35];
    int top = 0;
    do
    {
        sta[top++] = x % 10, x /= 10;
    } while (x);
    while (top)
        putchar(sta[--top] + 48); // 48 是 '0'
}
//end of quote
bool e[100005];
bool done[100005];
int main()
{
#ifdef DEBUG
    freopen("F:/Code/Algorithm/CppAlgorithm/PlayGround/in.txt", "r", stdin);
    //freopen("F:/Code/Algorithm/CppAlgorithm/PlayGround/out.txt", "w", stdout);
#endif
    int n , m;
    memset(e, false, sizeof(e));
    memset(done, false, sizeof(done));
    stack<int> q;

    while (~scanf("%d %d", &n, &m))
    {
        for (int i = 0; i < m; i++)
        {
            int move = read();
            e[move] == true;
            q.push(move);
        }
        for (int i = 0; i <= n; i++)
        {
            while (!q.empty()) {
                int temp = q.top();
                q.pop();
                if (done[temp] == false)
                {
                    done[temp] = true;
                    printf("%d \n", temp);
                }
            }
            
        }
        for (int i = 1; i <= n; i++)
        {
            if (done[i] == false)
            {
                printf("%d \n", i);
            }
        }
    }
    return 0;
}