SCU2016-01 D题 并查集判断连通

/**********************jibancanyang**************************
*Author*        :jibancanyang
*Created Time*  : 一  7/ 4 15:09:42 2016
**Problem**:

**Code**:
***********************1599664856@qq.com**********************/

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <stack>
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
#define pr(x) cout << #x << ": " << x << "  "
#define pl(x) cout << #x << ": " << x << endl;
#define pri(a) printf("%d\n",(a))
#define xx first
#define yy second
#define sa(n) scanf("%d", &(n))
#define sal(n) scanf("%lld", &(n))
#define sai(n) scanf("%I64d", &(n))
#define vep(c) for(decltype((c).begin() ) it = (c).begin(); it != (c).end(); it++)
const int mod = int(1e9) + 7, INF = 0x3f3f3f3f;
const int maxn = 500 + 13;
int l = 250000 + 2, r = 250000 + 3;
int par[maxn * maxn], rnk[maxn * maxn];
int G[maxn][maxn];
int dirx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
int diry[] = {0, 1, 1, 1, 0, -1, -1, -1};

void init(int n) {
par[l] = l;
par[r] = r;
rnk[l] = rnk[r] = 0;
for (int i = 0; i < n; i++) {

par[i] = i;
rnk[i] = 0;
}
}

int find(int x) {
if (x == par[x]) return x;
return find(par[x]);
}

void unite(int x, int y) {
x = find(x), y = find(y);
if (x == y) return;
if (rnk[x] < rnk[y]) {
par[x] = y;
} else {
par[y] = x;
if (rnk[x] == rnk[y]) rnk[x]++;
}
}

bool same(int a, int b) {
return find(a) == find(b);
}

int main(void)
{
#ifdef LOCAL
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif
int tt; sa(tt);
while (tt--) {
int n, m;
sa(n), sa(m);
init(n * m);
for (int i = 0; i < n; i++) {
char str[555];
scanf("%s", str);
for (int j = 0; j < m; j++) {
if (str[j] == '0') G[i][j] = 0;
else G[i][j] = 1;
}
}

for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (G[i][j] == 1) {
for (int k = 0; k < 8; k++) {
int x = i + dirx[k], y = j + diry[k];
if (x >= 0 && x < n && y >= 0 && y < m && G[x][y] == 1) {
unite(x * m + y, i * m + j);
}
}
if (j == 0) {
unite(i * m + j, l);
} else if (j == m - 1) {
unite(i * m + j, r);
}
}
}
}

int q; sa(q);
bool ok = false;int ans = 0;
for (int i = 0; i < q; i++) {
if (!ok && same(l, r)) {
ok = true;
ans = i;
}
int x1, y1;
sa(x1), sa(y1);
G[x1][y1] = 1;
if (!ok) for (int k = 0; k < 8; k++) {
int x = x1 + dirx[k], y = y1 + diry[k];
if (x >= 0 && x < n && y >= 0 && y < m && G[x][y] == 1) {
unite(x * m + y, x1 * m + y1);
}
if (y1 == 0) {
unite(x1 * m + y1, l);
} else if (y1 == m - 1) {
unite(x1 * m + y1, r);
}
}
}
if (!ok && same(l, r)) {
ok = true;
ans = q;
}
if (ok) pri(ans);
else pri(-1);
}
return 0;
}