【PAT】1048. Find Coins

#define LOCAL#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int MAXN=100000+10;int a[MAXN];int h[1000];int main(){    #ifdef LOCAL        freopen("data.in","r",stdin);        freopen("data.out","w",stdout);    #endif // LOCAL    int n,m;    cin>>n>>m;    for(int i=0;i<n;i++){        scanf("%d",&a[i]);        h[a[i]]++;    }    sort(a,a+n);    int i;    for(i=0;i<n;i++){        if(h[a[i]] && h[m-a[i]] &&a[i]*2!=m){            cout<<a[i]<<" "<<m-a[i];            break;        }else if(a[i]*2==m&&h[a[i]]>=2){            cout<<a[i]<<" "<<a[i];            break;        }    }    if(i==n) cout<<"No Solution";    return 0;}

注意哈希表开的数组要足够大，每个元素虽然不超过500但是m-500可能超过500