图的遍历——BFS（队列实现）

复制代码#include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <queue> #include <malloc.h> using namespace std; const int VERTEX_NUM = 20; const int INFINITY = 0x7fffffff; // 最大int型数，表示权的无限值 bool vis[VERTEX_NUM]; class Graph { public: int vexNum; int edgeNum; int vex[VERTEX_NUM]; int arc[VERTEX_NUM][VERTEX_NUM]; }; void createGraph(Graph &G) { cout << "please input vexNum and edgeNum: "; cin >> G.vexNum >> G.edgeNum; for (int i = 0; i != G.vexNum; ++i) { cout << "please input no" << i+1 << " vertex: "; cin >> G.vex[i]; } for (int i = 0; i != G.vexNum; ++i) { for (int j = 0; j != G.vexNum; ++j) { G.arc[i][j] = INFINITY; } } for (int k = 0; k != G.edgeNum; ++k) { cout << "please input the vertex of edge(vi, vj) and weight: "; int i, j, w; cin >> i >> j >> w; G.arc[i][j] = w; G.arc[j][i] = G.arc[i][j]; // 无向图 } } void BFSTraverse(const Graph &G) { memset(vis, false, VERTEX_NUM); queue<int> q; for (int i = 0; i != G.vexNum; ++i) { if (!vis[i]) { vis[i] = true; cout << G.vex[i] << " "; q.push(i); while (!q.empty()) { int m = q.front(); // 队列的作用正在于此 q.pop(); // ... for (int j = 0; j != G.vexNum; ++j) { if (G.arc[m][j] != INFINITY && !vis[j]) { cout << G.vex[j] << " "; q.push(j); vis[j] = true; } } } } } } int main() { Graph G; createGraph(G); BFSTraverse(G); return 0; }

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#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <malloc.h>
using namespace std;
const int VERTEX_NUM = 20;
const int INFINITY = 0x7fffffff;
// 最大int型数，表示权的无限值
bool vis[VERTEX_NUM];
class Graph {
public:
int vexNum;
int edgeNum;
int vex[VERTEX_NUM];
int arc[VERTEX_NUM][VERTEX_NUM];
};
void createGraph(Graph &G)
{
cout << "please input vexNum and edgeNum: ";
cin >> G.vexNum >> G.edgeNum;
for (int i = 0; i != G.vexNum; ++i) {
cout << "please input no" << i+1 << " vertex: ";
cin >>
G.vex[i];
}
for (int i = 0; i != G.vexNum; ++i) {
for (int j = 0; j != G.vexNum; ++j) {
G.arc[i][j] = INFINITY;
}
}
for (int k = 0; k != G.edgeNum; ++k) {
cout << "please input the vertex of edge(vi, vj) and weight: ";
int i, j, w;
cin >> i >> j >> w;
G.arc[i][j] = w;
G.arc[j][i] = G.arc[i][j];
// 无向图
}
}
void BFSTraverse(const Graph &G)
{
memset(vis, false, VERTEX_NUM);
queue<int> q;
for (int i = 0; i != G.vexNum; ++i) {
if (!vis[i]) {
vis[i] = true;
cout << G.vex[i] << " ";
q.push(i);
while (!q.empty()) {
int m = q.front();	// 队列的作用正在于此
q.pop();
// ...
for (int j = 0; j != G.vexNum; ++j) {
if (G.arc[m][j] != INFINITY && !vis[j]) {
cout << G.vex[j] << " ";
q.push(j);
vis[j] = true;
}
}
}
}
}
}
int main()
{
Graph G;
createGraph(G);
BFSTraverse(G);
return 0;
}