/***********************************************最大流算法(dinic)在深搜时，刚开始没有把d[cur] = -1超时，改之后就好了相当于一个剪枝操作***********************************************/#include <iostream>#include <queue>#include <cstring>#include <fstream>#include <cstdio>using namespace std;const int MAXD = 7200;const int MAXM = 36000;const int INF = 1000000000;int first[MAXD], next[MAXM], u[MAXM], v[MAXM], flow[MAXM];int d[MAXD];int s, a, b;int e;void init();void add(int x, int y, int f);int bfs();int dfs(int cur, int f);int dinic();int main(int argc, char *argv[]){ int t;#ifndef ONLINE_JUDGE freopen("d:\\OJ\\uva_in.txt", "r", stdin);#endif // ONLINE_JUDGE scanf("%d", &t); while (t--) { init(); int ans = dinic(); if (ans) printf("possible\n"); else printf("not possible\n"); } return 0;}void init(){ e = 0; //cin >> s >> a >> b; scanf("%d%d%d", &s, &a, &b); memset(first, -1, sizeof(first)); memset(flow, 0, sizeof(flow)); for (int i = 1; i <= a; i++) { int z = a + i; add(2 * z ^ 1, 1, 1); add(1, 2 * z ^ 1, 0); } for (int i = 1; i <= s; i++) { int z = i * a + 1; add(2 * z ^ 1, 1, 1); add(1, 2 * z ^ 1, 0); } for (int i = 1; i <= a; i++) { int z = s * a + i; add(2 * z ^ 1, 1, 1); add(1, 2 * z ^ 1, 0); } for (int i = 1; i <= s; i++) { int z = i * a + a; add(2 * z ^ 1, 1, 1); add(1, 2 * z ^ 1, 0); } for (int i = 1; i <= s; i++) { for (int j = 1; j <= a; j++) { int z = i * a + j; add(2 * z, 2 * z ^ 1, 1); add(2 * z ^ 1, 2 * z, 0); if (i + 1 <= s) { int newz = (i + 1) * a + j; add(2 * z ^ 1, 2 * newz, 1); add(2 * newz, 2 * z ^ 1, 0); add(2 * newz ^ 1, 2 * z, 1); add(2 * z, 2 * newz ^ 1, 0); } if (j + 1 <= a) { int newz = i * a + j + 1; add(2 * z ^ 1, 2 * newz, 1); add(2 * newz, 2 * z ^ 1, 0); add(2 * newz ^ 1, 2 * z, 1); add(2 * z, 2 * newz ^ 1, 0); } } } for (int i = 0; i < b; i++) { int x, y, z; scanf("%d%d", &x, &y); z = x * a + y; add(0, 2 * z, 1); add(2 * z, 0, 0); }}void add(int x, int y, int f){ u[e] = x; v[e] = y; flow[e] = f; next[e] = first[x]; first[x] = e; e++;}int bfs(){ queue<int> q; memset(d, -1, sizeof(d)); q.push(0); d[0] = 0; while (!q.empty()) { int u1 = q.front(); q.pop(); for (int j = first[u1]; j != -1; j = next[j]) { if (flow[j] > 0 && d[v[j]] == -1) { d[v[j]] = d[u1] + 1; if (v[j] == 1) return 1; q.push(v[j]); } } } return 0;}int dfs(int cur, int f){ if (cur == 1 || f == 0) return f; int ans = 0; for (int j = first[cur]; j != -1; j = next[j]) { if (flow[j] > 0 && d[v[j]] == d[cur] + 1) { int t = dfs(v[j], flow[j] < f ? flow[j]:f); flow[j] -= t; flow[j ^ 1] += t; f -= t; ans += t; if (f == 0) break; } } d[cur] = -1; return ans;}int dinic(){ int ans = 0; while (bfs()) { ans += dfs(0, INF); } if (ans == b) return 1; else return 0;}
