(Codeforces)East Central North America Regional Contest 2016–H Vin Diagrams
题意
用两个不规则的方形表示两个韦恩图,求两个韦恩图的单独部分和公共部分的面积。
思路
先把这两个图分开,并记录中间的公共部分的圈(中间公共部分的圈是不能接触到整个图的边界的)。然后对空的部分搜索,如果搜索的时候只碰到中间公共部分的圈,则就是中间公共部分的面积。如果搜索的时候搜索到非中间公共部分的圈的A圈的部分,则是A圈的单独部分,反之就是B圈的公共部分。
坑定
各种判断,很容易写错。
代码
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define per(i,a,b) for(int i=a;i>=b;i--)
const int N=105;
const ll MOD=998244353;
const int PI=acos(-1);
const int EPS=1e-9;
const int dx[]={0,0,1,-1};
const int dy[]={1,-1,0,0};
char state[N][N];
int out[N][N];
int vis[N][N];
struct S
{
int x,y;
};
inline void init(int r,int c)
{
rep(i,0,r+3)rep(j,0,c+3)state[i][j]='.';
}
inline bool _road(int x,int y)
{
if(x<0||y<0)return false;
if(state[x][y]=='X')return true;
else return false;
}
inline bool __road(int x,int y)
{
if(state[x][y]=='A')return true;
else return false;
}
int main()
{
int r,c;scanf("%d%d",&r,&c);
init(r,c);
rep(i,1,r){scanf("%s",state[i]+1);state[i][c+1]='.';}
int x_a,y_a,x_b,y_b;
rep(i,1,r)
rep(j,1,c)
if(state[i][j]=='A'){x_a=i;y_a=j;}
else if(state[i][j]=='B'){x_b=i;y_b=j;}
int x=x_a,y=y_a;
char sta='U';
while(1)
{
switch(sta)
{
case 'U':
if(_road(x-1,y)==true){
x--;
if((_road(x,y+1)==false&&_road(x,y-1)==false)
||_road(x-1,y)==false)state[x][y]='A';
}
else
{
if(_road(x,y+1)==true){y++;sta='R';}
else if(_road(x,y-1)==true){y--;sta='L';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_a;y=y_a;}
else x--;
state[x][y]='A';
}
break;
case 'D':
if(_road(x+1,y)==true){
x++;
if((_road(x,y+1)==false&&_road(x,y-1)==false)
||_road(x+1,y)==false)state[x][y]='A';
}
else
{
if(_road(x,y+1)==true){y++;sta='R';}
else if(_road(x,y-1)==true){y--;sta='L';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_a;y=y_a;}
else x++;
state[x][y]='A';
}
break;
case 'L':
if(_road(x,y-1)==true){
y--;
if((_road(x+1,y)==false&&_road(x-1,y)==false)
||_road(x,y-1)==false)state[x][y]='A';
}
else
{
if(_road(x+1,y)==true){x++;sta='D';}
else if(_road(x-1,y)==true){x--;sta='U';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_a;y=y_a;}
else y--;
state[x][y]='A';
}
break;
case 'R':
if(_road(x,y+1)==true){
y++;
if((_road(x-1,y)==false&&_road(x+1,y)==false)
||_road(x,y+1)==false)state[x][y]='A';
}
else
{
if(_road(x+1,y)==true){x++;sta='D';}
else if(_road(x-1,y)==true){x--;sta='U';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_a;y=y_a;}
else y++;
state[x][y]='A';
}
break;
}
if(x==x_a&&y==y_a)break;
}
x=x_b,y=y_b;
sta='U';
while(1)
{
switch(sta)
{
case 'U':
if(_road(x-1,y)==true){
x--;
if((_road(x,y+1)==false&&_road(x,y-1)==false)
||_road(x-1,y)==false)state[x][y]='B';
}
else
{
if(_road(x,y+1)==true){y++;sta='R';}
else if(_road(x,y-1)==true){y--;sta='L';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_b;y=y_b;}
else x--;
state[x][y]='B';
}
break;
case 'D':
if(_road(x+1,y)==true){
x++;
if((_road(x,y+1)==false&&_road(x,y-1)==false)
||_road(x+1,y)==false)state[x][y]='B';
}
else
{
if(_road(x,y+1)==true){y++;sta='R';}
else if(_road(x,y-1)==true){y--;sta='L';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_b;y=y_b;}
else x++;
state[x][y]='B';
}
break;
case 'L':
if(_road(x,y-1)==true){
y--;
if((_road(x+1,y)==false&&_road(x-1,y)==false)
||_road(x,y-1)==false)state[x][y]='B';
}
else
{
if(_road(x+1,y)==true){x++;sta='D';}
else if(_road(x-1,y)==true){x--;sta='U';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_b;y=y_b;}
else y--;
state[x][y]='B';
}
break;
case 'R':
if(_road(x,y+1)==true){
y++;
if((_road(x-1,y)==false&&_road(x+1,y)==false)
||_road(x,y+1)==false)state[x][y]='B';
}
else
{
if(_road(x+1,y)==true){x++;sta='D';}
else if(_road(x-1,y)==true){x--;sta='U';}
else if(_road(x-1,y)==false&&_road(x+1,y)==false
&&_road(x,y-1)==false&&_road(x,y+1)==false){x=x_b;y=y_b;}
else y++;
state[x][y]='B';
}
break;
}
if((__road(x,y+1)==true&&__road(x,y-1)==true)
||(__road(x+1,y)==true&&__road(x-1,y)==true))state[x][y]='X';
if(x==x_b&&y==y_b) break;
}
queue<S> Q1;
Q1.push(S{0,0});
out[0][0]=1;
while(!Q1.empty())
{
S now=Q1.front();
Q1.pop();
rep(i,0,3)
{
S nex;
nex.x=now.x+dx[i],nex.y=now.y+dy[i];
if(nex.x<0||nex.y>c+2||nex.y<0||nex.y>r+2)continue;
if(out[nex.x][nex.y]==1)continue;
if(state[nex.x][nex.y]=='.'){out[nex.x][nex.y]=1;Q1.push(nex);}
else out[nex.x][nex.y]=1;
}
}
rep(i,0,r+2)rep(j,0,c+2)vis[i][j]=out[i][j];
int flag=0;///flag为0表示是公共部分,1表示A,2表示B
int ans0,ans1,ans2;
rep(i,1,r)
{
rep(j,1,c)
{
if(vis[i][j]==1||state[i][j]!='.')continue;
int num=1;
queue<S> Q;
Q.push(S{i,j});
vis[i][j]=1;
while(!Q.empty())
{
flag=0;
S now=Q.front();
Q.pop();
rep(i,0,3)
{
S nex;
nex.x=now.x+dx[i];
nex.y=now.y+dy[i];
if(vis[nex.x][nex.y]==0&&state[nex.x][nex.y]=='.')
{
vis[nex.x][nex.y]=1;
num++;
Q.push(nex);
}
else
{
if(out[nex.x][nex.y]==1)
if(state[nex.x][nex.y]=='A')flag=1;
else flag=2;
}
}
}
if(flag==0)ans0=num;
else if(flag==1)ans1=num;
else if(flag==2)ans2=num;
}
}
printf("%d %d %d\n",ans1,ans2,ans0);
return 0;
}