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Diffstat (limited to 'count_num_complete_component.c')
-rw-r--r-- | count_num_complete_component.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/count_num_complete_component.c b/count_num_complete_component.c new file mode 100644 index 0000000..a6ede23 --- /dev/null +++ b/count_num_complete_component.c @@ -0,0 +1,73 @@ +// 2685. Count the Number of Complete Components +#include "leetcode.h" + +/* + * you are given an integer 'n'. there is an undirected graph with 'n' vertices, + * numbered from 0 to 'n - 1'. you are given a 2d integer array 'edges' where + * 'edges[i] = [a_i, b_i]' denotes that there exists an undirected edge + * connecting vertices 'a_i' and 'b_i'. return the number of complete connected + * components of the graph. a connected component is a subgraph of a graph in + * which there exists a path between any two vertices and no vertex of the + * subgraph shares an edge with a vertex outside of the subgraph. a connected + * component is said to be complete if there exists an edge between every pair + * of its vertices + */ + +int countCompleteComponents(int n, int **edges, int edgesSize, + int *edgesColSize) { + int *vertices = (int *)calloc(n, sizeof(int)); + int *edge_cnt = (int *)calloc(n, sizeof(int)); + int *vert_cnt = (int *)calloc(n, sizeof(int)); + int group = 1, ans = 0; + for (int i = 0; i < edgesSize; i++) { + int v1 = edges[i][0]; + int v2 = edges[i][1]; + if (!(vertices[v1] + vertices[v2])) { + vertices[v1] = vertices[v2] = group; + edge_cnt[group] = 2; + vert_cnt[group++] = 1; + } else if (!vertices[v1]) { + vertices[v1] = vertices[v2]; + ++edge_cnt[vertices[v2]]; + ++vert_cnt[vertices[v2]]; + } else if (!vertices[v2]) { + vertices[v2] = vertices[v1]; + ++edge_cnt[vertices[v1]]; + ++vert_cnt[vertices[v1]]; + } else if (vertices[v1] == vertices[v2]) + ++vert_cnt[vertices[v1]]; + else { + vert_cnt[vertices[v1]] += vert_cnt[vertices[v2]] + 1; + edge_cnt[vertices[v1]] += edge_cnt[vertices[v2]]; + edge_cnt[vertices[v2]] = vert_cnt[vertices[v2]] = 0; + for (int i = 0; i < n; i++) + if (vertices[i] == vertices[v2]) + vertices[i] = vertices[v1]; + } + } + int connect_cnt = 0; + for (int i = 1; i < group; i++) { + int edges = edge_cnt[i], verts = vert_cnt[i]; + if (edges && (edges * (edges - 1) / 2 == verts)) + ++ans; + connect_cnt += edges; + } + free(vert_cnt); + free(edge_cnt); + free(vertices); + return ans + (n - connect_cnt); +} + +int main() { + int e1i[4][2] = {{0, 1}, {0, 2}, {1, 2}, {3, 4}}, + e2i[5][2] = {{0, 1}, {0, 2}, {1, 2}, {3, 4}, {3, 5}}; + struct two_d_arr e1, e2; + two_d_arr_init(&e1, ARRAY_SIZE(e1i), ARRAY_SIZE(e1i[0]), e1i); + two_d_arr_init(&e2, ARRAY_SIZE(e2i), ARRAY_SIZE(e2i[0]), e2i); + printf("%d\n", countCompleteComponents(6, e1.arr, e1.row_size, + e1.col_size)); // expect: 3 + printf("%d\n", countCompleteComponents(6, e2.arr, e2.row_size, + e2.col_size)); // expect: 1 + two_d_arr_free(&e1); + two_d_arr_free(&e2); +} |