hdu 4775 Infinite Go(暴力)

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題目連結：hdu 4775 Infinite Go

題目大意：兩個人下圍棋，總共走了n步，黑棋和白棋交替走，如果一片棋的上下左右被封死，那麼該片棋子就會被吃掉，問說最後黑白棋各剩多少個。

解題思路：比較噁心的類比題，相鄰相同色的棋子要用並查集串連，並且要記錄每片棋子還剩的空格數，如果空格數為0的話說明該片棋子被其他顏色圍住，則要剔除掉，不且將相鄰的位置不同色的棋空格數加1。主要是細節上的問題。

範例
8
7
5 5
4 5
3 5
3 4
4 4
3 3
4 6
18
1 3
1 4
2 2
1 5
2 4
2 3
3 1
3 2
3 5
3 4
4 2
4 3
4 4
1 6
5 3
3 3
1 10
3 3
12
1 2
1 1
2 1
2 2
1 3
3 1
2 3
1 4
3 2
3 3
4 2
2 4
4
1 1
1 2
2 2
2 1
4
2000000000 2000000000
2000000000 1999999999
1999999999 1999999999
1999999999 2000000000
8
1 2
4 1
2 1
4 2
2 3
4 3
3 2
2 2
17
1 3
1 4
2 2
1 5
2 4
2 3
3 1
3 2
3 5
3 4
4 2
4 3
4 4
1 6
5 3
30 30
3 3
17
1 3
1 4
2 2
1 5
2 4
2 3
3 1
3 2
3 5
3 4
4 2
3 3
4 4
1 6
5 3
4 3
100 100
答案
4 2
9 4
6 4
1 2
2 2
4 3
9 4
9 3

#include <cstdio>#include <cstring>#include <vector>#include <map>#include <queue>#include <algorithm>using namespace std;const int maxn = 1e4;const int INF = 2*1e9+10;const int dir[4][2] = { {0, 1}, {0, -1}, {1, 0}, {-1, 0} };typedef pair<int, int> pii;int N, Nw, Nb, X[maxn+5], Y[maxn+5], f[maxn+5], c[maxn+5];map<pii, int> R;void init () {    scanf("%d", &N);    Nw = N / 2;    Nb = N - Nw;    R.clear();    for (int i = 0; i < N; i++) {        f[i] = i;        c[i] = 0;    }}inline int bit (int x) {    return x&1;}int getfar (int x) {    return f[x] == x ? x : f[x] = getfar(f[x]);}inline bool isEmpty (int x, int y) {    if (x <= 0 || y <= 0 || x >= INF || y >= INF)        return false;    if (R.count(make_pair(x, y)))        return false;    return true;}inline int count_empty (pii u) {    int cnt = 0;    for (int i = 0; i < 4; i++) {        int x = u.first + dir[i][0];        int y = u.second + dir[i][1];        if (isEmpty(x, y))            cnt++;    }    return cnt;}inline void link_board (int x, int y) {    int fx = getfar(x);    int fy = getfar(y);    f[fy] = fx;    c[fx] += c[fy];    /**/    c[fx]--;}int del_board (int col, int x, int y) {    int cnt = 1;    pii u = make_pair(x, y);    queue<pii> que;    que.push(u);    f[R[u]] = R[u];    R.erase(u);    while (!que.empty()) {        u = que.front();        que.pop();        for (int i = 0; i < 4; i++) {            int p = u.first + dir[i][0];            int q = u.second + dir[i][1];            if (p <= 0 || p >= INF || q <= 0 || q >= INF)                continue;            pii v = make_pair(p, q);            if (!R.count(v))                continue;            int set = R[v];            if (bit(set) != col) {                int k = getfar(set);                c[k]++;                continue;            }            f[R[v]] = R[v];            R.erase(v);            cnt++;            que.push(v);        }    }    return cnt;} void del_empty (int k) {    int fk = getfar(k);    c[fk]--;    if (c[fk] == 0) {        int set = bit(fk);        int cnt = del_board(set, X[fk], Y[fk]);        if (set)            Nw -= cnt;        else            Nb -= cnt;    }}void solve () {    for (int i = 0; i < N; i++) {        scanf("%d%d", &X[i], &Y[i]);        pii v = make_pair(X[i], Y[i]);        c[i] = count_empty(v);        R[v] = i;        for (int j = 0; j < 4; j++) {            int p = X[i] + dir[j][0];            int q = Y[i] + dir[j][1];            if (p <= 0 || q <= 0 || p >= INF || q >= INF)                continue;            pii u = make_pair(p, q);            if (!R.count(u))                continue;            int k = R[u];            if (bit(i) == bit(k))                link_board(i, k);            else                del_empty(k);        }        int fi = getfar(i);        if (c[fi] == 0) {            int cnt = del_board(bit(fi), X[fi], Y[fi]);            if (bit(fi))                Nw -= cnt;            else                Nb -= cnt;        }    }    printf("%d %d\n", Nb, Nw);}int main () {    int cas;        scanf("%d", &cas);    while (cas--) {        init();        solve();    }    return 0;}