Submission #885315

#	Time	Username	Problem	Language	Result	Execution time	Memory
885315		alexdd	Bomb (IZhO17_bomb)	C++17	44 / 100	337 ms	55636 KiB

bomb

#include<iostream>
using namespace std;
int n,m;
char mat[2505][2505];
int sump[2505][2505];
int mars[2505][2505];
bool verif(int cntx, int cnty)
{
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            mars[i][j]=0;
    for(int i=1;i+cntx-1<=n;i++)
    {
        for(int j=1;j+cnty-1<=m;j++)
        {
            if(sump[i+cntx-1][j+cnty-1] - sump[i+cntx-1][j-1] - sump[i-1][j+cnty-1] + sump[i-1][j-1] == cntx*cnty)///toate is 1
            {
                mars[i][j]++;
                mars[i][j+cnty]--;
                mars[i+cntx][j]--;
                mars[i+cntx][j+cnty]++;
            }
        }
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            mars[i][j] += mars[i-1][j] + mars[i][j-1] - mars[i-1][j-1];
            if(mars[i][j]==0 && mat[i][j]=='1')
                return 0;
        }
    }
    return 1;
}
signed main()
{
    cin>>n>>m;
    int minx=n,miny=m;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            cin>>mat[i][j];
            sump[i][j] = sump[i-1][j] + sump[i][j-1] - sump[i-1][j-1];
            if(mat[i][j]=='1')
                sump[i][j]++;
        }
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            if(mat[i][j]=='1' && (j==m || mat[i][j+1]=='0'))
            {
                int cnt=0;
                for(int u=j;u>0;u--)
                {
                    if(mat[i][u]=='0')
                        break;
                    cnt++;
                }
                miny = min(miny, cnt);
            }
        }
    }
    for(int i=1;i<=m;i++)
    {
        for(int j=1;j<=n;j++)
        {
            if(mat[j][i]=='1' && (j==n || mat[j+1][i]=='0'))
            {
                int cnt=0;
                for(int u=j;u>0;u--)
                {
                    if(mat[u][i]=='0')
                        break;
                    cnt++;
                }
                minx = min(minx, cnt);
            }
        }
    }
    if(1LL*minx * miny * n * m > 200000000)
    {
        cout<<minx*miny;
        return 0;
    }
    //minx=n;miny=m;
    int poz=0, mxm=0;
    for(int i=minx;i>0;i--)
    {
        if(i*miny <= mxm)
            break;
        while(poz+1<=miny && verif(i,poz+1))
        {
            poz++;
        }
        mxm = max(mxm, i*poz);
    }
    cout<<mxm;
    return 0;
}

• Subtask 1: 44 / 100