CodeForces – 752B

CodeForces – 752B
https://vjudge.net/problem/597648/origin
简单模拟，主要是细节
特殊情况多考虑一下，看代码就行

#include<iostream>
#include<cstdio>
#include<queue>
#include<algorithm>
#include<cmath>
#include<ctime>
#include<set>
#include<map>
#include<stack>
#include<cstring>
#define inf 2147483647
#define ls rt<<1
#define rs rt<<1|1
#define lson ls,nl,mid,l,r
#define rson rs,mid+1,nr,l,r
#define N 100010
#define For(i,a,b) for(int i=a;i<=b;i++)
#define p(a) putchar(a)
#define g() getchar()using namespace std;
char c1[N],c2[N];
int n,a[N],cnt;
bool b[N];
void in(int &x){
    int y=;
    char c=g();x=;
    while(c<''||c>''){
        if(c=='-')y=-;
        c=g();
    }
    while(c<=''&&c>=''){
        x=(x<<)+(x<<)+c-'';c=g();
    }
    x*=y;
}
void o(int x){
    if(x<){
        p('-');
        x=-x;
    }
    if(x>)o(x/);
    p(x%+'');
}
int main(){
    cin>>(c1+)>>(c2+);
    n=strlen(c1+);
    For(i,,n){
        if(c1[i]==c2[i]&&!a[(int)c1[i]]){
            a[(int)c1[i]]=(int)c1[i];
        }
        else
            if(c1[i]!=c2[i]&&!a[(int)c1[i]]&&!a[(int)c2[i]]){
                a[(int)c1[i]]=(int)c2[i];
                a[(int)c2[i]]=(int)c1[i];
                cnt++;
            }
            else
                if(c1[i]!=c2[i]&&(a[(int)c1[i]]!=(int)c2[i]||a[(int)c2[i]]!=(int)c1[i])){
                    o(-);
                    return ;
                }
                else
                    if(c1[i]==c2[i]&&a[(int)c1[i]]!=(int)c1[i]){
                        o(-);
                        return ;
                    }
    }
    o(cnt);p('\n');
    For(i,,n){
        if(c1[i]!=c2[i]&&!b[c1[i]]){
            p(c1[i]);p(' ');p(c2[i]);p('\n');
            b[c1[i]]=b[c2[i]]=;
        }
    }
    return ;
}