CUBE-066: dog_village

#include<bits/stdc++.h>
using namespace std;
int n,m,mp[1010][1010],sur,dayIn[1010][1010],getInf[1010][1010];
bool infected[1010][1010];

void isInf(int i,int j,int day){
    if(i<1||j< 1||i>n||j>m){exit;}

    else if(mp[i][j]>day){
        if(getInf[i][j]>day){
            getInf[i][j]=day;
            isInf(i+1,j,day+1);
            isInf(i-1,j,day+1);
            isInf(i,j+1,day+1);
            isInf(i,j-1,day+1);
        }
        else if(!infected[i][j]){
        infected[i][j]=true;
            sur++;
            getInf[i][j]=day;
            isInf(i+1,j,day+1);
            isInf(i-1,j,day+1);
            isInf(i,j+1,day+1);
            isInf(i,j-1,day+1);
        }
     }
}

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

    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            scanf("%d",&mp[i][j]);
        }
    }

    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(mp[i][j]==0){
                infected[i][j]=true; sur++;
                isInf(i+1,j,1);
                isInf(i-1,j,1);
                isInf(i,j+1,1);
                isInf(i,j-1,1);
            }
        }
    }


    printf("%d",(n*m)-sur);

    return 0;
}