为啥25分啊（只过最后一个点）

_TeaClaudz_ @ 2023-08-07 20:44:14

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

int n;
char st[7] = "ABCDEF";

void add(string &a) {
    string b = a;
    reverse(b.begin(), b.end());
    int na[105], nb[105], l = a.length();
    for(int i = 0; i < l; ++i) {
        na[l - i - 1] = isdigit(a[i])?a[i]-'0':a[i]-'A'+10;
        nb[l - i - 1] = isdigit(b[i])?b[i]-'0':b[i]-'A'+10;
    }
    for(int i = 0; i < l; ++i) {
        na[i] += nb[i];
        if(na[i] >= n) na[i+1]+=na[i]/n, na[i]%=n;
    }
    if(na[l]) l++;
    for(int i = 0; i < l; ++i) {
        a[i] = na[l - i - 1] < 10?na[l-i-1]+'0':st[na[l-i-1]-10];
    }
}

int main() {
    string a, t;
    cin >> n >> a;
    for(int i = 0; i <= 30; ++i) {
        t = a;
        reverse(t.begin(), t.end());
        if(t == a) {
            cout << "STEP=" << i;
            return 0;
        }
        add(a);
    }
    cout << "Impossible!";
    return 0;
}

by _TeaClaudz_ @ 2023-08-07 20:47:26

测试点输出全是"Impossible!",不知道什么问题T_T

by I_am_a_rookie_O @ 2023-08-07 21:08:59

证明判断条件未执行，有可能是你递归出错

by _TeaClaudz_ @ 2023-08-07 21:14:38

@DU654321 新的代码，但是只有本地能过

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

int n;
char st[17] = "0123456789ABCDEF";

void add(string &a) {
    string b = a;
    reverse(b.begin(), b.end());
    int na[105], nb[105], l = a.length();
    for(int i = 0; i < l; ++i) {
        na[l - i - 1] = isdigit(a[i])?a[i]-'0':a[i]-'A'+10;
        nb[l - i - 1] = isdigit(b[i])?b[i]-'0':b[i]-'A'+10;
    }
    int x;
    /*
    a1=8 a0=7 b1=7 b0=8
    a0=7+8=15
    x=1
    a0=5
    a1=8+7+1=16
    x=1
    a1=6
    */
    for(int i = 0; i < l; ++i) {
        na[i] += nb[i] + x;
        x = na[i] / n;
        na[i] %= n;
    }
    if(x) na[l] = x, l++;
    while(na[l] == '0') l--;
    //cout << l << endl;
    a.clear();
    for(int i = l - 1; i >= 0; --i) {
        a += st[na[i]];
        //cout << st[na[i]] << " a:"<< a << endl;
    }
}

int main() {
    string a, t;
    cin >> n >> a;
    for(int i = 0; i < 30; ++i) {
        t = a;
        reverse(t.begin(), t.end());
        //cout << "a:" << a << " t:" << t << endl;
        if(t == a) {
            cout << "STEP=" << i;
            return 0;
        }
        add(a);
    }
    cout << "Impossible!";
    return 0;
}

by _TeaClaudz_ @ 2023-08-07 21:15:41

@DU654321 奥，结论出来了，x没初始化（）

by I_am_a_rookie_O @ 2023-08-07 21:20:44

聪明，6我居然没想到T-T