【915程序设计】20西交大软件专硕915程序设计真题讲解_2023年西安交通大学915真题

1. abcd+cabd=7856

#include<bits/stdc++.h>
using namespace std;

int main() {
	for(int a=1;a<=6;++a){
		for(int b=0;b<=9;++b){
			for(int c=1;c<=6;++c){
				for(int d=0;d<=9;++d){
					int x=a*1000+b*100+c*10+d;
					int y=c*1000+a*100+b*10+d;
					if(x+y==7856){
						cout<<a<<" "<<b<<" "<<c<<" "<<d<<endl;
					}
				}
			}
		}
	} 
	return 0;
}
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2. 反序数

#include<bits/stdc++.h>
using namespace std;

int reverse(int number){
	vector<int> nums;
	while(number){
		nums.push_back(number%10);
		number/=10;
	}
	number=0;
	int temp=1;
	for(int i=nums.size()-1;i>=0;--i){
		number+=nums[i]*temp;
		temp*=10;
	}
	return number;
}

int judge(int x,int y){
	return (reverse(x)+reverse(y))==(x+y);
}

int main() {
	vector<int> xs,ys;
	int n,x,y;
	cin>>n;
	for(int i=0;i<n;++i){
		cin>>x>>y;
		if(judge(x,y)){
			xs.push_back(x);
			ys.push_back(y);
		}
	}
	if(xs.size()){
		for(int i=0;i<xs.size();++i){
			cout<<xs[i]<<" "<<ys[i]<<endl;
		}
	}else{
		cout<<"none";
	}
	return 0;
}
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3. 商品

#include<bits/stdc++.h>
using namespace std;

vector<int> p;
int num,price;
int cnt;

void f(int i,int price,vector<int>& buy){
	if(i==num&&price!=0){
		return;
	}
	
	if(price==0){
		++cnt;
		
		for(int j=0;j<buy.size();++j){
			cout<<buy[j]<<" ";
		}
		cout<<endl;
		return;
	}
	
	f(i+1,price,buy);
	if(price>=p[i]){
		buy.push_back(i);
		f(i+1,price-p[i],buy);
		buy.pop_back();
	}
}

int main() {
	cin>>num>>price;
	for(int i=0;i<num;++i){
		int temp;
		cin>>temp;
		p.push_back(temp); 
	}
	vector<int> buy;
	f(0,price,buy);
	cout<<cnt;
	return 0;
}
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