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#include <iostream>
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#include <algorithm>
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#include <vector>
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#include <queue>
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#include <cstring>
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using namespace std;
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bool ok;
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int n, m;
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vector <short> colored;
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vector < vector <int> > graph;
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void bfs(int start)
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{
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queue<int> bfsQ;
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bfsQ.push(start);
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colored[start] = 0;
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while (!bfsQ.empty() && ok)
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{
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int top = bfsQ.front();
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bfsQ.pop();
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for (int i = 0; i < graph[top].size(); i++)
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{
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int child = graph[top][i];
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if (colored[child] == colored[top])
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{
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ok = false;
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}
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else if (colored[child] == -1)
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{
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colored[child] = !colored[top];
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bfsQ.push(child);
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}
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}
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}
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}
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int main()
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{
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while (cin >> n, n != 0)
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{
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cin >> m;
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ok = true;
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graph.clear();
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colored.clear();
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graph.resize(n);
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colored.resize(n, -1);
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for (int i = 0; i < m; i++)
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{
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int x, y;
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cin >> x >> y;
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graph[x].push_back(y);
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graph[y].push_back(x);
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}
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bfs(0);
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printf("%s\n", ok ? "BICOLORABLE." : "NOT BICOLORABLE.");
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}
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} |
