[SCOI2007]蜥蜴

这一题就是网络流啦！QaQ
模版+构图就好
就是构图有点难

for(int i=1;i<=n;i++){
        scanf("%s",s+1);
        for(int j=1;j<=m;j++){
            K[i][j]=s[j]-'0';
            Nh[i][j]=(m*(i-1)+j);
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            Ch[i][j]=Nh[i][j]+n*m;
            if(K[i][j]>0)ins(Nh[i][j],Ch[i][j],K[i][j]);
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(i<=d||j<=d||i>=n-d+1||j>=m-d+1){
                ins(Ch[i][j],ed,999999999);
            }
        }
    }
    answer=0;
    for(int i=1;i<=n;i++){
        scanf("%s",s+1);
        for(int j=1;j<=m;j++){
            if(s[j]=='L'){
                answer++;ins(st,Nh[i][j],1);
            }
        } 
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            int n1,n2,n3,n4;
            n1=max(i-d,1);n2=min(i+d,n);
            n3=max(j-d,1);n4=min(j+d,m);
            for(int x=n1;x<=n2;x++){
                for(int y=n3;y<=n4;y++){
                    if(pd(i,j,x,y)<=d){
                        if(x!=i||y!=j){
                            ins(Ch[i][j],Nh[x][y],999999999);
                        }
                    }
                }
            }
        }
    }

长长的构图啊。累啊~QaQ
大家快点提交吧
提交传送门

#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
using namespace std;
struct node{
    int x,y,c,next,other;
}a[1100000];int len,first[1100000];
int n,m,d,list[1100000],head,tail,st,ed,K[1100][1100],ans,answer,h[1100000],Nh[1100][1100],Ch[1100][1100];
char s[1100];
double pd(int x,int y,int x1,int y1){
    return sqrt(double((x-x1)*(x-x1)+(y-y1)*(y-y1)));
}
void ins(int x,int y,int c){
    int xx,yy;
    len++;xx=len;
    a[len].x=x;a[len].y=y;a[len].c=c;
    a[len].next=first[x];first[x]=len;
    len++;yy=len;
    a[len].x=y;a[len].y=x;a[len].c=0;
    a[len].next=first[y];first[y]=len;
    a[xx].other=yy;
    a[yy].other=xx;
}
bool bt(){
    memset(h,0,sizeof(h));h[st]=1;
    list[1]=st;head=1;tail=2;
    while(head!=tail){
        int x=list[head];
        for(int k=first[x];k>0;k=a[k].next){
            int y=a[k].y;
            if(a[k].c>0&&h[y]==0){
                h[y]=h[x]+1;
                list[tail++]=y;
            }
        }
        head++;
    }
    if(h[ed]>0)return true;
    else return false;
}
int findflow(int x,int f){
    if(x==ed)return f;
    int s=0,tmp;
    for(int k=first[x];k>0;k=a[k].next){
        int y=a[k].y;
        if(a[k].c>0&&h[y]==h[x]+1&&s<f){
            tmp=findflow(y,min(a[k].c,f-s));
            s+=tmp;
            a[k].c-=tmp;a[a[k].other].c+=tmp;
        }
    }
    if(s==0)h[x]=0;
    return s;
}
int main(){
    scanf("%d%d%d",&n,&m,&d);
    st=0;ed=10001;
    len=0;memset(first,0,sizeof(first));
    for(int i=1;i<=n;i++){
        scanf("%s",s+1);
        for(int j=1;j<=m;j++){
            K[i][j]=s[j]-'0';
            Nh[i][j]=(m*(i-1)+j);
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            Ch[i][j]=Nh[i][j]+n*m;
            if(K[i][j]>0)ins(Nh[i][j],Ch[i][j],K[i][j]);
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(i<=d||j<=d||i>=n-d+1||j>=m-d+1){
                ins(Ch[i][j],ed,999999999);
            }
        }
    }
    answer=0;
    for(int i=1;i<=n;i++){
        scanf("%s",s+1);
        for(int j=1;j<=m;j++){
            if(s[j]=='L'){
                answer++;ins(st,Nh[i][j],1);
            }
        } 
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            int n1,n2,n3,n4;
            n1=max(i-d,1);n2=min(i+d,n);
            n3=max(j-d,1);n4=min(j+d,m);
            for(int x=n1;x<=n2;x++){
                for(int y=n3;y<=n4;y++){
                    if(pd(i,j,x,y)<=d){
                        if(x!=i||y!=j){
                            ins(Ch[i][j],Nh[x][y],999999999);
                        }
                    }
                }
            }
        }
    }
    ans=0;
    while(bt()==true){
        ans+=findflow(st,999999999);
    }
    printf("%d\n",answer-ans);
    return 0;
}