124 lines
3.0 KiB
C++
124 lines
3.0 KiB
C++
#include <stdio.h>
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// 并查集。并查集只关注双向连通性。
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struct Edge {
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int next;
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unsigned short end;
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bool used_in_dfs;
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};
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Edge edges[1050000];
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char nodes_visited[65540];
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int head[65540], len;
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int add_edge(int start, int terminal) {
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edges[++len].end = terminal;
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edges[len].next = head[start];
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head[start] = len;
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return 0;
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}
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int dfs(int start) {
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if (nodes_visited[start] >= 1) {
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// nodes_visited[start] = 2;
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return 0;
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}
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nodes_visited[start] = 1;
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for (int j = head[start]; j != 0; j = edges[j].next) {
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edges[j].used_in_dfs = dfs(edges[j].end);
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}
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return 1;
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}
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int dfs_with_dead_edge(int start, int dead_edge_start, int dead_edge_end) {
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if (nodes_visited[start] >= 1) {
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return 0;
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}
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nodes_visited[start] = 1;
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if (start == dead_edge_start) {
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for (int j = head[start]; j != 0; j = edges[j].next) {
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if (edges[j].end == dead_edge_end) {
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continue;
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}
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dfs_with_dead_edge(edges[j].end, dead_edge_start, dead_edge_end);
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}
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return 0;
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}
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for (int j = head[start]; j != 0; j = edges[j].next) {
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dfs_with_dead_edge(edges[j].end, dead_edge_start, dead_edge_end);
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}
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return 0;
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}
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int main() {
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int N, M;
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scanf("%d %d", &N, &M);
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for (int start = 0; start < N; start++) {
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int edge_count;
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scanf("%d", &edge_count);
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for (int j = 0; j < edge_count; j++) {
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int terminal;
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scanf("%d", &terminal);
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add_edge(start, terminal);
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}
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}
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dfs(0);
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for (int i = 0; i < N; i++) {
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if (nodes_visited[i] < 1) {
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// Not connected!
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for (int j = 0; j <= M; j++) {
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printf("0\n");
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}
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return 0;
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}
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}
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printf("1\n");
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// for (int i = 0; i < M; i++) {
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// int start, end;
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// scanf("%d %d", &start, &end);
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// if (nodes_visited[end] == 2) {
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// printf("1\n");
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// }
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// else {
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// printf("0\n");
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// }
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// }
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for (int i = 0; i < M; i++) {
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int start, end;
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scanf("%d %d", &start, &end);
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for (int j = head[start]; j != 0; j = edges[j].next) {
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if (edges[j].end == end) {
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if (edges[j].used_in_dfs) {
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for (int k = 0; k < N; k++) {
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nodes_visited[k] = 0;
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}
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dfs_with_dead_edge(0, start, end);
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bool connected = true;
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for (int k = 0; k < N; k++) {
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if (nodes_visited[k] < 1) {
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printf("0\n");
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connected = false;
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break;
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}
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}
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if (connected) {
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printf("1\n");
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}
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}
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else {
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printf("1\n");
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}
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break;
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}
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}
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}
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return 0;
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} |