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34 lines
602 B
C++
34 lines
602 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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int n, m, x, y, ans, f[100005];
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int find(int x) {
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if (f[x] == x) return x;
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return f[x] = find(f[x]);
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}
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void unity(int x, int y) {
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f[find(x)] = find(y);
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}
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int main() {
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while (cin >> n, n) {
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ans = 0;
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cin >> m;
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for (int i = 1; i <= n; i++) {
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f[i] = i;
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}
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for (int i = 1; i <= m; i++) {
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cin >> x >> y;
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unity(x, y);
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}
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for (int i = 1; i <= n; i++) {
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if (find(i) == i) ans++;
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}
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cout << --ans << endl;
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}
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return 0;
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}
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