71E - Nuclear Fusion - CodeForces Solution

// LUOGU_RID: 115684560
#include <iostream>
#include <string>
#include <vector>
using namespace std;
const int M = 20;
string s[]={" ","H","He","Li","Be","B","C","N","O","F","Ne","Na","Mg","Al","Si","P","S","Cl","Ar","K","Ca","Sc","Ti","V","Cr","Mn","Fe","Co","Ni","Cu","Zn","Ga","Ge","As","Se","Br","Kr","Rb","Sr","Y","Zr","Nb","Mo","Tc","Ru","Rh","Pd","Ag","Cd","In","Sn","Sb","Te","I","Xe","Cs","Ba","La","Ce","Pr","Nd","Pm","Sm","Eu","Gd","Tb","Dy","Ho","Er","Tm","Yb","Lu","Hf","Ta","W","Re","Os","Ir","Pt","Au","Hg","Tl","Pb","Bi","Po","At","Rn","Fr","Ra","Ac","Th","Pa","U","Np","Pu","Am","Cm","Bk","Cf","Es","Fm"};
int n,m,a[M],b[M],f[M][1<<18];
string t;vector<int> v;
int work(string x){
	for(int i=1;i<=100;i++)
		if(s[i]==x) return i;
}
void print(){
	int sum=0,j=0;
	for(int i=0;i<v.size();i++){
		sum+=v[i];
		cout<<s[v[i]];
		if(sum==b[j]){
			printf("->");
			cout<<s[b[j++]];
			puts("");sum=0;
		}
		else printf("+");
	}
	exit(0);
}
void dfs(int x,int sum,int s){
	if(sum==b[x]){
		if(x==m){
			puts("YES");
			print();
		}
		else dfs(x+1,0,s);
		return ;
	}
	if(sum>b[x]) return ;
	if(f[x][s]) return ;
	for(int i=0;i<n;i++){
		if(s&(1<<i)) continue;
		v.push_back(a[i]);
		dfs(x,sum+a[i],s|(1<<i));
		v.pop_back();
	}
	f[x][s]=1;
}
signed main(){
	cin>>n>>m;
	for(int i=0;i<n;i++){
		cin>>t;
		a[i]=work(t);
	}
	for(int i=0;i<m;i++){
		cin>>t;
		b[i]=work(t);
	}
	dfs(0,0,0);cout<<"NO";
	return 0;
}