mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-12-18 01:51:58 +00:00
71 lines
1.3 KiB
C++
71 lines
1.3 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 1e6 + 5;
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int t, n, m, q, cnt, block[N], color[N];
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std::vector<int> g[N];
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bool flag[N];
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void dfs(int u, int f) {
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block[u] = cnt;
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for (int v : g[u]) {
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if (color[v] != -1 && color[u] == color[v]) {
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flag[cnt] = true;
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} else if (color[v] == -1) {
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color[v] = color[u] ^ 1;
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dfs(v, u);
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}
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}
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> t >> n >> m;
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for (int i = 1, u, v; i <= m; i++) {
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cin >> u >> v;
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g[u].emplace_back(v);
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g[v].emplace_back(u);
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}
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std::fill_n(color, N, -1);
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for (int i = 1; i <= n; i++) {
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if (color[i] == -1) {
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cnt++;
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color[i] = 0;
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dfs(i, 0);
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}
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}
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cin >> q;
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while (q--) {
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int s, t;
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cin >> s >> t;
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if (s == t) {
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cout << 0 << endl;
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} else if (block[s] != block[t]) {
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cout << -1 << endl;
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} else if (flag[block[s]] || color[s] != color[t]) {
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cout << 1 << endl;
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} else {
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cout << 2 << endl;
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}
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}
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return 0;
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}
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