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author | Jack Sangdahl <[email protected]> | 2024-06-29 18:33:35 -0600 |
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committer | Jack Sangdahl <[email protected]> | 2024-06-29 18:33:35 -0600 |
commit | 0cea53b366c1ef1b94693772b8f3c3299fcd699b (patch) | |
tree | 07af9d255265eee3845554934147a2fdf51a9ce7 | |
parent | 31c33591e4be1cc400e4de23b7fe097c7513e35c (diff) | |
download | leetcode-0cea53b366c1ef1b94693772b8f3c3299fcd699b.tar.gz leetcode-0cea53b366c1ef1b94693772b8f3c3299fcd699b.zip |
1579. remove max number edges graph
-rw-r--r-- | remove_max_num_edge_traverse.c | 76 | ||||
-rw-r--r-- | remove_max_num_edge_traverse.cpp (renamed from remove_max_edge.cpp) | 0 | ||||
-rw-r--r-- | remove_max_num_edge_traverse.py | 73 |
3 files changed, 149 insertions, 0 deletions
diff --git a/remove_max_num_edge_traverse.c b/remove_max_num_edge_traverse.c new file mode 100644 index 0000000..3dda41a --- /dev/null +++ b/remove_max_num_edge_traverse.c @@ -0,0 +1,76 @@ +// 1579. Remove Max Number of Edges to Keep Graph Fully Traversable +#include "leetcode.h" + +/* + * alice and bob have an undirected graph of 'n' nodes and three + * types of edges: + * type1: can be traversed by alice only + * type2: can be traversed by bob only + * type3: can be traversed by both alice and bob + * given an array of 'edges' where 'edges{i} = {typei, ui, vi}' + * represents a bidirectional edge of type 'typei' between nodes + * 'ui' and 'vi', find the maximum number of edges you can remove + * so that after removing the edges, the graph can still be fully + * traversed by alice and bob if starting from any node, they can + * reach all other nodes. return the maximum number of edges you + * can remove, or return -1 if alice and bob cannot traverse graph + */ + +int find(int *n, int target) { + return n[target] < 0 ? target : (n[target] = find(n, n[target])); +} + +int connect(int *n, int x, int y) { + int a = find(n, x), b = find(n, y); + if (a == b) + return 0; + if (n[a] > n[b]) + n[a] = b; + else if (n[b] > n[a]) + n[b] = a; + else { + n[a] = b; + n[b]--; + } + return 1; +} + +int maxNumEdgesToRemove(int n, int **edges, int edgesSize, int *edgesColSize) { + int e = 0, f = 0, g = 0, b = n, c = n, d = n; + int *p = (int *)malloc(n * sizeof(*p)); + int *q = (int *)malloc(n * sizeof(*q)); + int *r = (int *)malloc(n * sizeof(*r)); + for (int i = 0; i < n; ++i) + p[i] = q[i] = r[i] = -1; + for (int i = 0; i < edgesSize; i++) { + int t = edges[i][0], u = edges[i][1] - 1, v = edges[i][2] - 1; + if (t != 1) { + e++; + b -= connect(p, u, v); + } + if (t != 2) { + f++; + d -= connect(q, u, v); + } + if (t == 3) { + g++; + d -= connect(r, u, v); + } + } + free(p), free(q), free(r); + return b > 1 || c > 1 ? -1 : e + f - g + b + c - d - n; +} + +int main() { + int e1[6][3] = {{3, 1, 2}, {3, 2, 3}, {1, 1, 3}, + {1, 2, 4}, {1, 1, 2}, {2, 3, 4}}; + int e2[4][3] = {{3, 1, 2}, {3, 2, 3}, {1, 1, 4}, {2, 1, 4}}; + int e3[3][3] = {{3, 2, 3}, {1, 1, 2}, {2, 3, 4}}; + int ecs1[] = {6, 6, 6}, ecs2[] = {4, 4, 4}, ecs3[] = {3, 3, 3}; + printf("%d\n", maxNumEdgesToRemove(4, (int **)e1, ARRAY_SIZE(e1), + (int *)ARRAY_SIZE(e1[0]))); // expect: 2 + printf("%d\n", maxNumEdgesToRemove(4, (int **)e2, ARRAY_SIZE(e2), + (int *)ARRAY_SIZE(e2[0]))); // expect: 0 + printf("%d\n", maxNumEdgesToRemove(4, (int **)e3, ARRAY_SIZE(e3), + (int *)ARRAY_SIZE(e3[0]))); // expect: -1 +} diff --git a/remove_max_edge.cpp b/remove_max_num_edge_traverse.cpp index fb73f0b..fb73f0b 100644 --- a/remove_max_edge.cpp +++ b/remove_max_num_edge_traverse.cpp diff --git a/remove_max_num_edge_traverse.py b/remove_max_num_edge_traverse.py new file mode 100644 index 0000000..3aee386 --- /dev/null +++ b/remove_max_num_edge_traverse.py @@ -0,0 +1,73 @@ +# 1579. Remove Max Number of Edges to Keep Graph Fully Traversable + +""" +alice and bob have an undirected graph of 'n' nodes and three +types of edges: +type1: can be traversed by alice only +type2: can be traversed by bob only +type3: can be traversed by both alice and bob +given an array of 'edges' where 'edges{i} = {typei, ui, vi}' +repansents a bidirectional edge of type 'typei' between nodes +'ui' and 'vi', find the maximum number of edges you can remove +so that after removing the edges, the graph can still be fully +traversed by alice and bob if starting from any node, they can +reach all other nodes. return the maximum number of edges you +can remove, or return -1 if alice and bob cannot traverse graph +""" + + +class Solution(object): + def maxNumEdgesToRemove(self, n, edges): + """ + :type n: int + :type edges: List[List[int]] + :rtype: int + """ + def find(i): + if i != root[i]: + root[i] = find(root[i]) + return root[i] + def uni(x, y): + x, y = find(x), find(y) + if x == y: + return 0 + root[x] = y + return 1 + ans,e1,e2=0,0,0 + root = range(n + 1) + for t, i, j in edges: + if t == 3: + if uni(i, j): + e1 += 1 + e2 += 1 + else: + ans += 1 + root0 = root[:] + for t, i, j in edges: + if t == 1: + if uni(i, j): + e1 += 1 + else: + ans += 1 + root = root0 + for t, i, j in edges: + if t == 2: + if uni(i, j): + e2 += 1 + else: + ans += 1 + return ans if e1 == e2 == n - 1 else -1 + + +if __name__ == "__main__": + obj = Solution() + print( + obj.maxNumEdgesToRemove( + n=4, + edges=[[3, 1, 2], [3, 2, 3], [1, 1, 3], [1, 2, 4], [1, 1, 2], [2, 3, 4]], + ) + ) + print( + obj.maxNumEdgesToRemove(n=4, edges=[[3, 1, 2], [3, 2, 3], [1, 1, 4], [2, 1, 4]]) + ) + print(obj.maxNumEdgesToRemove(n=4, edges=[[3, 2, 3], [1, 1, 2], [2, 3, 4]])) |