用STL的stack超时了…

#include<iostream>
#include<algorithm>

using namespace std;

const int N = 3010;

int n, m;
int g[N][N];

void get(int h[], int bound[])
{
    int s[N], tt = -1;
    for (int i = 1; i <= m; i++)
    {
        while (tt >= 0 && h[i] <= h[s[tt]])  tt--;

        if (tt >= 0) bound[i] = s[tt];
        else    bound[i] = 0;
        s[++tt] = i;
    }
}

int main()
{
    int p;
    scanf("%d%d%d", &n, &m, &p);

    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            g[i][j] = 1;

    while (p--)
    {
        int a, b;
        scanf("%d%d", &a, &b);
        g[a][b] = 0;
    }
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            if (g[i][j] == 1)
                g[i][j] += g[i - 1][j];

    int res = 0;
    for (int i = 1; i <= n; i++)
    {
        int l[N], r[N];

        get(g[i], l);
        reverse(g[i] + 1, g[i] + 1 + m);
        get(g[i], r);

        int ans = 0;
        for (int p = 1, q = m; p <= m; p++, q--)
            ans = max(ans, g[i][q] * (m - r[q] - l[p]));

        res = max(res, ans);
    }
    printf("%d", res);
    return 0;
}