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matchesequation

admin 11月 12, 2020 0

One day, AD1024 and Neli playing a game, they are using N matches to create equations: X+Y=Z(‘+’ and ‘=’ also created by using matches).
But they are too weak to work out every possible conditions, so they decide to ask you for help. You are a battlehardened programmer, so you can solve this problem by using programming.

Problem Description

Problem Analysis

This problem looks very hard, but it’s pretty easy. We can pre-process the number of matches that will be used creating number N.打表打表打表.

##AC Code

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

int matches[10]={6,2,5,5,4,5,6,3,7,6};
int b[1001];
int ans;
int main(){
    freopen("matches.in","r",stdin);
    freopen("matches.out","w",stdout);
    int n;
    cin>>n;
    n-=4;
    for(int i=0;i<10;++i){
        b[i]=matches[i];
    }
    for(int i=10;i<=999;++i){
        b[i]=b[i/10]+b[i%10];
    }
    ans=0;
    for(int i=0;i<=999;++i){
        if(b[i]<n){
            for(int j=0;j<=i;++j){
                if(b[i]+b[j]+b[i-j]==n){
                    ans++;
                }
            }
        }
    }
    cout<<ans;
    fclose(stdin);
    fclose(stdout);
    return 0;
}