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yukicoder No.348
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>
#define repd(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repd(i,0,n)
#define all(x) (x).begin(),(x).end()
#define mod 1000000007
#define inf 2000000007
#define mp make_pair
#define pb push_back
typedef long long ll;
using namespace std;
template <typename T>
inline void output(T a, int p) {
if(p) cout << fixed << setprecision(p) << a << "\n";
else cout << a << "\n";
}
// end of template
// union find
class union_find {
public:
int n;
vector<int> parent, rnk, num;
union_find(int n) : n(n), parent(n), rnk(n, 0), num(n, 1) {rep(i, n) parent[i] = i; }
int root(int x){ return (parent[x] == x) ? x : root(parent[x]); }
void unite(int x, int y){
x = root(x);
y = root(y);
if (x == y) {
return;
}
if (rnk[x] < rnk[y]) {
parent[x] = y;
num[y] += num[x];
}
else{
parent[y] = x;
num[x] += num[y];
if (rnk[x] == rnk[y]) {
rnk[x]++;
}
}
n--;
}
bool same(int x, int y) {return root(x) == root(y);}
int count(int x){ return num[root(x)]; }
};
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
int H, W;
vector<int> vis;
vector<vector<int>> G, T, dp;
vector<string> S;
void dfs(int pos, int ring, union_find &uf){
vis[pos] = 1;
for(int c: G[pos]){
int cx = c % W, cy = c / W;
rep(k, ring ? 8 : 4){
if (cx + dx[k] >= 0 && cx + dx[k] < W && cy + dy[k] >= 0 && cy + dy[k] < H) {
if (S[cy + dy[k]][cx + dx[k]] == ring ? '.' : 'x' && vis[uf.root((cy + dy[k]) * W + cx + dx[k])] == 0) {
T[pos].pb(uf.root((cy + dy[k]) * W + cx + dx[k]));
dfs(uf.root((cy + dy[k]) * W + cx + dx[k]), ring ^ 1, uf);
}
}
}
}
}
void dfs_m(int now, union_find &uf){ // 一番浅いところにあるxの輪すべてについてこの操作を行う メモ化再帰
dp[now][1] = uf.count(now);
for(int ch: T[now]) for(int chch : T[ch]){
dfs_m(chch, uf);
dp[now][0] += max(dp[chch][0], dp[chch][1]);
dp[now][1] += dp[chch][0];
}
}
int main() {
cin.tie(0);
ios::sync_with_stdio(0);
// source code
cin >> H >> W;
H += 2, W += 2;
S.resize(H);
S[0] = S[H - 1] = string(W, '.');
rep(i, H - 2){
cin >> S[i + 1];
S[i + 1] = '.' + S[i + 1] + '.';
}
union_find uf(H * W);
rep(y, H) rep(x, W){
rep(k, S[y][x] == 'x' ? 8 : 4){
if (!(x + dx[k] >= 0 && x + dx[k] < W && y + dy[k] >= 0 && y + dy[k] < H)) continue;
if (S[y + dy[k]][x + dx[k]] == S[y][x]){
uf.unite(y * W + x, (y + dy[k]) * W + x + dx[k]);
}
}
}
vis.assign(H * W, 0), G.resize(H * W), T.resize(H * W), dp.resize(H * W, vector<int>(2));
rep(i, H * W) G[uf.root(i)].pb(i);
dfs(uf.root(0), 0, uf);
int ret = 0;
for (int x: T[uf.root(0)]) {
dfs_m(x, uf);
ret += max(dp[x][0], dp[x][1]);
}
output(ret, 0);
return 0;
}
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