不开O2

开O2

mycode:

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int N = 30;
int n;
char s[3][N];
int q[N], w[N];
bool vis[N];
bool check()
{
    for (int i=n-1,t=0;i>=0;i--)
    {
        int a = s[0][i] - 'A', b = s[1][i] - 'A', c = s[2][i] - 'A';
        a = w[a], b = w[b], c = w[c];
        if (a != -1 && b != -1 && c != -1)
        {
            if (t != -1)
            {
                if ((a + b + t) % n != c)
                    return false;
                if (!i && a + b + t >= n)
                    return false;
                t = (a + b + t) / n;
            }
            else
            {
                if ((a + b) % n != c && (a + b + 1) % n != c)
                    return false;
                if (!i && a + b >= n)
                    return false;
            }
        }
        else
            t = -1;
    }
    return true;
}
bool dfs(int u)
{
    if (u == n)
        return true;
    for (int i=n-1;i>=0;i--)
        if (!vis[i])
        {
            w[q[u]] = i;
            vis[i] = true;
            if (check() && dfs(u + 1))
                return true;
            w[q[u]] = -1;
            vis[i] = false;
        }
}
int main()
{
    scanf("%d",&n);
    for (int i=0;i<3;i++)
        scanf("%s", s[i]);
    for (int i=n-1,k=0;i>=0;i--)
        for (int j=0;j<3;j++)
        {
            int t = s[j][i] - 'A';
            if (!vis[t])
            {
                q[k ++] = t;
                vis[t] = true;
            }
        }
    memset(vis, false, N);
    memset(w, -1, sizeof w);
    dfs(0);
    for (int i=0;i<n;i++)
        printf("%d ", w[i]);
    return 0;
}