[dfs基础]XXX+XXX=XXX

#include<cstdio>using namespace std;int a[10],book[10],sum=0;void dfs(int step){	int i;	if(step==10){		if(a[1]*100+a[2]*10+a[3]+a[4]*100+a[5]*10+a[6]==a[7]*100+a[8]*10+a[9]){			sum++;			PRintf("%d%d%d+%d%d%d=%d%d%d/n",a[1],a[2],a[3],a[4],a[5],a[6],a[7],a[8],a[9]);		}		return;	}	for(i=1;i<=9;i++){		if(book[i]==0){			a[step]=i;			book[i]=1;			dfs(step+1);			book[i]=0;		}	}	return;}int main(){	dfs(1);	printf("The sum of all way is %d",sum/2);	return 0;}