package com.heu.wsq.leetcode.bingchaji;
public class RegionsBySlashes {
public int regionsBySlashes(String[] grid){
int N = grid.length;
int size = 4 * N * N;
UnionFind unionFind = new UnionFind(size);
for (int i = 0; i < N; i++){
for (int j = 0; j < N; j++){
char c = grid[i].charAt(j);
int index = 4 * (i * N + j);
if (c == '\\'){
unionFind.union(index, index + 1);
unionFind.union(index + 2, index + 3);
}else if (c == '/'){
unionFind.union(index, index + 3);
unionFind.union(index + 1, index + 2);
}else if (c == ' '){
unionFind.union(index, index + 1);
unionFind.union(index + 2, index + 3);
unionFind.union(index + 1, index + 2);
}
if (j + 1 < N){
unionFind.union(index + 1, index + 7);
}
if (i + 1 < N){
unionFind.union(index + 2, index + 4 * N);
}
}
}
return unionFind.count;
}
private class UnionFind{
private int[] parent;
private int count;
public UnionFind(int n){
this.parent = new int[n];
this.count = n;
for (int i = 0; i < n; i++) {
this.parent[i] = i;
}
}
public void union(int x, int y){
int rootX = find(x);
int rootY = find(y);
if (rootX == rootY){
return;
}
this.parent[rootX] = rootY;
this.count--;
}
public int find(int x){
return x != this.parent[x] ? find(this.parent[x]) : this.parent[x];
}
}
}