单独开 vis 记录有没有算过

#include <bits/stdc++.h>
using namespace std;
bool vis[1005][1005]; // 标记每组参数有没有算过
bool book[1005][1005];
bool dfs(int a, int b)
{
    if (a > b)
        swap(a, b);
    if (vis[a][b] == true)
        return book[a][b];
    if (b % a == 0)
        return true;
    // 在 b 减去 i 个 a
    for (int i = 1; i * a <= b; i++)
        if (dfs(a, b - i * a) == false)
        {
            vis[a][b] = true;
            return book[a][b] = true;
        }
    vis[a][b] = true;
    return book[a][b] = false;
}
int main()
{
    int a, b;
    while (cin >> a >> b)
    {
        if (a == 0 && b == 0)
            break;
        if (dfs(a, b))
            cout << "win\n";
        else
            cout << "lose\n";
    }
    return 0;
}

在 book 中同时记录有没有算过

#include <bits/stdc++.h>
using namespace std;
// -1 表示没算过，0 表示假，1 表示真
int book[1005][1005];
bool dfs(int a, int b)
{
    if (a > b)
        swap(a, b);
    if (book[a][b] != -1)
        return book[a][b];
    if (b % a == 0)
        return true;
    // 在 b 减去 i 个 a
    for (int i = 1; i * a <= b; i++)
        if (dfs(a, b - i * a) == false)
            return book[a][b] = true;
    return book[a][b] = false;
}
int main()
{
    for (int i = 1; i <= 1000; i++)
        for (int j = 1; j <= 1000; j++)
            book[i][j] = -1;
    int a, b;
    while (cin >> a >> b)
    {
        if (a == 0 && b == 0)
            break;
        if (dfs(a, b))
            cout << "win\n";
        else
            cout << "lose\n";
    }
    return 0;
}