打表

#include <bits/stdc++.h>
using namespace std;
int a[40][40];
queue<pair<int, int>> q;
int dx[] = {2, 2, 1, 1, -2, -2, -1, -1};
int dy[] = {1, -1, 2, -2, 1, -1, 2, -2};
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    for (int i = 1; i <= 40; i++)
        for (int j = 1; j <= 40; j++)
            a[i][j] = -1;
    q.push(make_pair(20, 20));
    a[20][20] = 0;
    while (!q.empty())
    {
        pair<int, int> now = q.front();
        q.pop();
        for (int i = 0; i < 8; i++)
        {
            int nx = now.first + dx[i];
            int ny = now.second + dy[i];
            if (1 <= nx && nx <= 40 &&
                1 <= ny && ny <= 40 &&
                a[nx][ny] == -1)
            {
                a[nx][ny] = a[now.first][now.second] + 1;
                q.push(make_pair(nx, ny));
            }
        }
    }
    for (int i = 20; i <= 30; i++)
    {
        for (int j = 20; j <= 30; j++)
            cout << a[i][j] << ",";
        cout << "\n";
    }
    return 0;
}
/*
0,3,2,3,2,3,4,5,4,5,6,
3,2,1,2,3,4,3,4,5,6,5,
2,1,4,3,2,3,4,5,4,5,6,
3,2,3,2,3,4,3,4,5,6,5,
2,3,2,3,4,3,4,5,4,5,6,
3,4,3,4,3,4,5,4,5,6,5,
4,3,4,3,4,5,4,5,6,5,6,
5,4,5,4,5,4,5,6,5,6,7,
4,5,4,5,4,5,6,5,6,7,6,
5,6,5,6,5,6,5,6,7,6,7,
6,5,6,5,6,5,6,7,6,7,8
*/

大范围贪心，小范围搜索枚举

#include <bits/stdc++.h>
using namespace std;
int len[11][11] = {
    0, 3, 2, 3, 2, 3, 4, 5, 4, 5, 6,
    3, 2, 1, 2, 3, 4, 3, 4, 5, 6, 5,
    2, 1, 4, 3, 2, 3, 4, 5, 4, 5, 6,
    3, 2, 3, 2, 3, 4, 3, 4, 5, 6, 5,
    2, 3, 2, 3, 4, 3, 4, 5, 4, 5, 6,
    3, 4, 3, 4, 3, 4, 5, 4, 5, 6, 5,
    4, 3, 4, 3, 4, 5, 4, 5, 6, 5, 6,
    5, 4, 5, 4, 5, 4, 5, 6, 5, 6, 7,
    4, 5, 4, 5, 4, 5, 6, 5, 6, 7, 6,
    5, 6, 5, 6, 5, 6, 5, 6, 7, 6, 7,
    6, 5, 6, 5, 6, 5, 6, 7, 6, 7, 8};
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int a, b, aa, bb;
    cin >> a >> b >> aa >> bb;
    // 算出要走的距离 +a +b，保证 a>=b
    a = abs(a - aa);
    b = abs(b - bb);
    if (a < b)
        swap(a, b);
    int ans = 0;
    // 贪心通过 +2 +1 完成 +a +b
    while (a >= 10 || b >= 10)
    {
        ans++;
        a = abs(a - 2);
        b = abs(b - 1);
        if (a < b)
            swap(a, b);
    }
    cout << ans + len[a][b];
    return 0;
}