2015安徽省赛 I.梯田

http://xcacm.hfut.edu.cn/problem.php?id=1213

set + 搜索

姐姐是用搜索+二分做的，效率要高很多

#include<iostream>
#include<cstdio>
#include<cstring>
#include<set>
using namespace std;
int x[]={ , ,-, };
int y[]={ ,-, , };
int lable[][],d[][];
int T,m,n,p,q,deepth=,cake=;
void dfs(int a,int b)
{
    if(d[a][b]>deepth||a<||a>=m||b<||b>=n||lable[a][b]==){return;}
    lable[a][b]=;
    cake++;
    for(int i=;i<;i++)
    {
        if(a+x[i]<||a+x[i]>=m||b+y[i]<||b+y[i]>=n){continue;}
        dfs(a+x[i],b+y[i]);
    }
    return;
}
void solve()
{
    int i,j;
    for(i=; i<m; i++)
    {
        if(lable[i][]==)
        {
            continue;
        }
        dfs(i,);
    }
    for(i=; i<m; i++)
    {
        if(lable[i][n-]==)
        {
            continue;
        }
        dfs(i,n-);
    }
    for(j=; j<n; j++)
    {
        if(lable[][j]==)
        {
            continue;
        }
        dfs(,j);
    }
    for(j=; j<n; j++)
    {
        if(lable[m-][j]==)
        {
            continue;
        }
        dfs(m-,j);
    }
}

int main()
{
    int i,j;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d%d%d",&m,&n,&p,&q);
        set<int>donser;
        for(i=;i<m;i++)
        {
            for(j=;j<n;j++)
            {
                scanf("%d",&d[i][j]);
                donser.insert(d[i][j]);
            }
        }
        while()
        {
            deepth=*donser.begin();
            solve();
            donser.erase(deepth);
            if(cake>=p&&cake<=q)
            {
                cout<<deepth<<endl;
                cake=;
                memset(lable,,sizeof(lable));
                memset(d,,sizeof(d));
                break;
            }
            if(donser.size()==||cake>q)
            {
                cout<<"-1"<<endl;
                cake=;
                memset(lable,,sizeof(lable));
                memset(d,,sizeof(d));
                break;
            }
            cake=;
            memset(lable,,sizeof(lable));
        }
    }
    return ;
}