HDU 4775 infinite go (query set, simulate)

HDU 4775 infinite go

Question Link

The two go players take turns. If one chain is surrounded, they will be eaten and asked how many games are left in black and white.

Idea: Simulate, use a parallel query set to save the chain, then record the number of spaces around it, and then simulate it. Note that When deleting, the space should be returned, and the location of the boundary will be enclosed.

Code:

#include <stdio.h>#include <string.h>#include <queue>#include <map>using namespace std;#define MP(a,b) make_pair(a,b)const int N = 10005;const int d[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};int T, n;typedef pair<int, int> pii;map<pii, int> vi, vis;int parent[N], sum[N], x[N], y[N];int find(int x) {    if (x == parent[x]) return x;    return parent[x] = find(parent[x]);}void init() {    scanf("%d", &n);    vi.clear();    for (int i = 1; i <= n; i++) {parent[i] = i; sum[i] = 0;scanf("%d%d", &x[i], &y[i]);    }}void del(int x, int y, int who) {    queue<pii> Q;    Q.push(MP(x, y));    vis.clear();    vis[MP(x,y)] = 1;    while (!Q.empty()) {pii now = Q.front();parent[vi[now]] = vi[now];sum[vi[now]] = 0;vi.erase(now);Q.pop();for (int i = 0; i < 4; i++) {    int xx = now.first + d[i][0];    int yy = now.second + d[i][1];    if (xx <= 0 || yy <= 0 || vis[MP(xx,yy)]) continue;    int tmp = vi[MP(xx,yy)];    if ((tmp&1)^who == 0) {vis[MP(xx,yy)] = 1;Q.push(MP(xx, yy));    }    else {int pt = find(tmp);sum[pt]++;    }}    }}void solve() {    for (int i = 1; i <= n; i++) {vi[MP(x[i],y[i])] = i;int empty = 0;for (int j = 0; j < 4; j++) {    int xx = x[i] + d[j][0];    int yy = y[i] + d[j][1];    if (xx <= 0 || yy <= 0) continue;    if (vi.count(MP(xx,yy)) == 0) {empty++;continue;    }    int pv = find(vi[MP(xx,yy)]);    sum[pv]--;}sum[i] = empty;for (int j = 0; j < 4; j++) {    int xx = x[i] + d[j][0];    int yy = y[i] + d[j][1];    if (xx <= 0 || yy <= 0) continue;    if (vi.count(MP(xx,yy)) == 0) continue;    if (((vi[MP(xx,yy)]&1)^(i&1)) == 0) {int pa = find(i);int pb = find(vi[MP(xx,yy)]);if (pa != pb) {    parent[pa] = pb;    sum[pb] += sum[pa];}    }    else {int pv = find(vi[MP(xx,yy)]);if (sum[pv] == 0)    del(xx, yy, vi[MP(xx,yy)]&1);    }}int pv = find(i);if (sum[pv] == 0)    del(x[i], y[i], i&1);    }    int ansa = 0, ansb = 0;    vis.clear();    for (int i = n; i >= 1; i--) {if (vi.count(MP(x[i],y[i])) == 0 || vis[MP(x[i], y[i])]) continue;vis[MP(x[i],y[i])] = 1;if (vi[MP(x[i],y[i])]&1) ansa++;else {    ansb++;}    }    printf("%d %d\n", ansa, ansb);}int main() {    scanf("%d", &T);    while (T--) {init();solve();    }    return 0;}