CODE FESTIVAL 2017 qual B B

CODE FESTIVAL 2017 qual B B - Problem Set

确实水题，但当时没想到map，用sort后逐个比较解决的，感觉麻烦些，虽然效率高很多。map确实好写点。

用map：

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<map>
using namespace std;
map<int,int>mp;

int main()
{
    int n,m,x;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>x;
        mp[x]++;
    }
    cin>>m;
    for(int i=0;i<m;i++){
        cin>>x;
        if(mp[x]==0){
            cout<<"NO"<<endl;
            exit(0);
        }else mp[x]--;
    }
    cout<<"YES"<<endl;
    return 0;
}

直接sort

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 200500;
int d[maxn], t[maxn];
 
int main()
{
    int N, M;
    scanf("%d", &N);
    for (int i = 1; i <= N; i++) scanf("%d", &d[i]);
    scanf("%d", &M);
    for (int i = 1; i <= M; i++) scanf("%d", &t[i]);
    sort(d+1, 1 + N+d);
    sort(t+1, 1 + M+t);
    int p1 = 1, p2 = 1;
    bool flag = false;
    while (p1<=M&&p2<=N)
    {
        if (p1 != M) {
            if (d[p2] == t[p1]) {
                p2++, p1++;
            }
            else {
                p2++;
            }
        }
        else
        {
            if (d[p2] == t[p1]) {
                flag = true;
                break;
            }
            else
            {
                p2++;
            }
        }
    }
    if (flag) printf("YES
");
    else printf("NO
");
    return 0;
}