for (int i = 1; i <= n; i++)
    {
        cin >> a[i].val;
        a[i].pos = i;
    }

    for (int i = 1; i <= n; i++)
    {
        cin >> b[i].val;
        b[i].pos = i;
    }

    sort(a + 1, a + 1 + n, cmp);
    sort(b + 1, b + 1 + n, cmp);

    for (int i = 1; i <= n; i++)
    {
        c[a[i].pos] = b[i].pos;
    }

结构体的离散化

for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        x[i] = a[i];
    }

    sort(x + 1, x + 1 +n);
    for (int i = 1; i <= n; i++)
    {
        a[i] = lower_bound(x + 1, x + 1 + n, a[i]) - x;
    }

    for (int i = 1; i <= n; i++)
    {
        cin >> b[i];
        x[i] = b[i];
    }

    sort(x + 1, x + 1 +n);
    for (int i = 1; i <= n; i++)
    {
        b[i] = lower_bound(x + 1, x + 1 + n, b[i]) - x;
    }

    for (int i = 1; i <= n; i++)
    {
        c[a[i]] = b[i];
    }

普通的离散化 用上面的写ac了,用下面的写只有10pts,其他代码一点没动,这是为什么