C++-蓝桥杯-颠倒的价牌[2013真题][水题][模拟]

#include <bits/stdc++.h>
using namespace std;
const int N=1e4;
int A[N],W[N],num[10]={0,1,2,-1,-1,5,9,-1,8,6};
int change(int x){
    int a=x%10;x/=10;
    int b=x%10;x/=10;
    int c=x%10;x/=10;
    int d=x%10;x/=10;
    a=num[a];if(a==-1)return -1;
    b=num[b];if(b==-1)return -1;
    c=num[c];if(c==-1)return -1;
    d=num[d];if(d==-1)return -1;
    int ans=a*1000+b*100+c*10+d;
    if(ans<1000)return -1;
    return ans;
}
bool check(int i,int j){
    if(W[i]+W[j]!=558)return false;
    if(W[i]>0)swap(i,j);
    int a=abs(W[i]),b=W[j];
    if(a>200&&a<300&&b>800&&b<900)return true;
    return false;
}
int main(){
    for(int i=1000;i<N;i++){
        A[i]=change(i);
        if(A[i]!=-1)
            W[i]=A[i]-i;
    }
    for(int i=1000;i<N;i++)
        for(int j=i+1;j<N;j++)
            if(check(i,j)){
                cout<<j<<endl;
                return 0;//cout<<i<<" "<<j<<endl;
            }
}