Uva1330/poj1964 City Game

这里 是针对这道题比较详细的讲解。

文章中指出的子问题是有例题的，具体见这里

#include <cstdio>
#include <stack>
#include <algorithm>
#include <iostream>
#include <cstring>
using namespace std;
const int MAXN = 1e3 + 20;

bool S[MAXN][MAXN];
int s[MAXN][MAXN];
int N, M;

struct rec // rectangle
{
    int l, h;
    rec(int l = 0, int h = 0) : l(l), h(h) {}
};
struct _Stack
{
    stack<rec> sta;

    inline void init()
    {
        while(!sta.empty())
            sta.pop();
    }

    inline int Pushin(rec now)
    {
        if(sta.empty() || sta.top().h < now.h)
        {
            sta.push(now);
            return 0;
        }

        rec cur;
        int len = 0, area = 0;
        while(!sta.empty() && now.h < sta.top().h)
        {
            cur = sta.top();
            len += cur.l;
            area = max(area, len * cur.h);
            sta.pop();
        }
        sta.push(rec(len + now.l, now.h));
        return area;
    }
}Stack;

inline void init()
{
    memset(S, false, sizeof(S));
    memset(s, 0, sizeof(s));
    Stack.init();
}

inline void solve()
{
    char ch;
    for(int i = 1; i <= N; i++)
        for(int j = 1; j <= M; j++)
        {
            cin>>ch;
            if(ch == 'F') S[i][j] = true;
            else S[i][j] = false;
        }

    for(int i = 1; i <= N; i++)
        for(int j = 1; j <= M; j++)
            S[i][j] == true ? s[i][j] = s[i - 1][j] + 1 : s[i][j] = 0;
        
    /*for(int i = 1; i <= N; i++)
        {
            for(int j = 1; j <= M; j++)
                cout<<s[i][j]<<" ";
            cout<<endl;
        }*/
    int area = 0;
    for(int i = 1; i <= N; i++)
    {
        for(int j = 1; j <= M; j++)
            area = max(area, Stack.Pushin(rec(1, s[i][j])));

        area = max(area, Stack.Pushin(rec(1, 0)));
        Stack.init();
    }    

    cout<<area * 3<<endl;
}

int main()
{
    //freopen("1330.txt", "r", stdin);
    ios::sync_with_stdio(false);
    int K;
    cin>>K;
    while(K--)
    {
        cin>>N>>M;
        init();
        solve();
    }
    return 0;
}