sysy-data/hidden_functional_c/sy/21_union_find.sy

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#include "sylib.h"
#define maxN 1005
int parent[maxN];
int find(int root) {
if (parent[root] == root)
return root;
else {
parent[root] = find(parent[root]);
return parent[root];
}
}
void merge(int p, int q) {
int root_p, root_q;
root_p = find(p);
root_q = find(q);
if (root_p != root_q) {
parent[root_q] = root_p;
}
return;
}
int main() {
int n = getint(), m = getint(), i;
int p, q;
i = 0;
while (i < n) {
parent[i] = i;
i = i + 1;
}
i = 0;
while (i < m) {
p = getint();
q = getint();
merge(p, q);
i = i + 1;
}
int clusters = 0;
i = 0;
while (i < n) {
if (parent[i] == i) clusters = clusters + 1;
i = i + 1;
}
putint(clusters);
return 0;
}