数据结构考试代码

最小生成树

//prim  算法
#include
#include
using namespace std;
int mp[3003][3003]; 
int vis[3003],d[3003];
int n,m;

void prim(){
	memset(d,0x3f,sizeof d);
	memset(vis,0,sizeof vis);
	d[1] = 0; 
	for(int i=1;i
		int x = 0;
		for(int j=1;j<=n;j++){
			if(!vis[j] && d[j] < d[x])  x = j;
		}
		vis[x] = 1;
		for(int j=1;j<=n;j++){
			if(!vis[j]){
				d[j] = min(mp[j][x],d[j]);
			}
		}
	}
}

int main(){
	memset(mp,0x3f,sizeof mp);
	int ans = 0,cnt = 0;
	cin >> n >> m;
	for(int i=1;i<=n;i++){
		mp[i][i] = 0;
	}
	for(int i=1;i<=m;i++){
		int u,v,w;
		cin >> u >> v >> w;
		mp[u][v] = mp[v][u] = min(mp[u][v],w);
	}
	prim();
	for(int i=2;i<=n;i++){
		if(d[i]){
			cnt++;
			if(ans < d[i]){
				ans = d[i];
			}
		}
	}
	cout << cnt << " " << ans;
}

//kruscal算法
//1.并查集写  其实书上也是用到了并查集没明说而已
#include
#include
#include
using namespace std;
const int maxn = 1e5+5;
struct Edge{
	int u,v,w;
	bool operator < (const Edge & e)const{
		return w < e.w;   // 重载< 运算符
	}
}e[maxn];//内存绝对够
int fa[maxn]; // 判断是不是在一个连通分量
int find(int x){
	if(fa[x] != x) fa[x] = find(fa[x]);  // 路径压缩
	return fa[x];
}

void merge(int a,int b){
	int x = find(a);  int y = find(b);
	fa[x] = y;
}

int main(){
	int n,m;
	int ans = 0 , cnt = 0;
	cin >> n >> m;
	for(int i=1;i<=n;i++){
		fa[i] = i ; // 预处理下
	}
	for(int i=1;i<=m;i++){
		int u,v,w;
		cin >> u >> v >> w;
		e[i].u = u, e[i].v = v,e[i].w = w;
	}
	sort(e+1,e+1+m) ;// 也可以用冒泡排序这里就不多写了
	for(int i=1;i<=m;i++){
		int u = e[i].u;
		int v = e[i].v;
		if(find(u) != find(v)){
			merge(u,v);
			cnt++;
			ans = e[i].w;
		}
	}
	cout << cnt << " " << ans ;
}

//dfs判断环
#include
#include
#include
#include
using namespace std;
const int maxn = 1e5 + 5;
int n, m;
int vis[maxn]; // 判断有没有被选
int vis2[maxn];
int ans = 0, cnt = 0,flag = 0;
vectorson[maxn];
struct Edge {
	int u, v, w;
	bool operator < (const Edge & e)const {
		return w < e.w;   // 重载< 运算符
	}
} e[maxn]; //内存绝对够

void dfs(int u,int v1){
	for(int i=0;i
		int v = son[u][i];
		if(vis2[v]) continue;
		vis2[v] = 1;
		if(vis[v]){
			if(v == v1){
				flag = 1;
				return;
			}
			else if(!flag){
				dfs(v,v1);
			}
		}
	}
}
void kruscal() {
	for(int i=1;i<=m;i++){
		int u = e[i].u;
		int v = e[i].v;
		memset(vis2,0,sizeof vis2);
		dfs(u,v);
		if(!flag && (!vis[u]||!vis[v])){
			vis[u] = vis[v] = 1;
			cnt++;
			ans = e[i].w;
		}
		flag = 0;
	}
}
int main() {
	memset(vis, 0, sizeof vis);
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		son[u].push_back(v);
		son[v].push_back(u);
		e[i].u = u, e[i].v = v, e[i].w = w;
	}
	sort(e + 1, e + 1 + m) ; // 也可以用冒泡排序这里就不多写了
	kruscal();
	cout << cnt << " " << ans;
}

//1.普通dijstra算法
#include
#include
#include
using namespace std;
const int maxn = 1e6 + 5;
struct Edge{
	int to,next,w;
};
Edge edge[maxn];
int d[maxn];
int vis[maxn], cnt = 0;
int n, m,head[maxn];
void add(int u,int v,int w){
	edge[++cnt].to = v;
	edge[cnt].next = head[u];
	edge[cnt].w = w;
	head[u] = cnt;
}
void dijstra() {
	for (int i = 1; i <= n - 1; i++) {
		int x = 0;
		for(int j = 1; j <= n; j++)
		if(!vis[j] && (x == 0 || (d[x] > d[j])))  x= j;
		vis[x] = 1;
		for(int i=head[x];i;i=edge[i].next){
			int v = edge[i].to;
			d[v] = min(d[v],d[x] + edge[i].w);
		}
	}
}
int main() {
	memset(d, 0x3f, sizeof(d));
	memset(vis, 0, sizeof(vis));
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		add(u,v,w);
		add(v,u,w);
	}
	d[1] = 0;
	dijstra();
	cout << d[n];
}

//2.堆优化的dijstra算法
#include
using namespace std;
#include
#include
#include
#include
const int maxn = 1e4+5;
int d[maxn],vis[maxn];
struct edge{
	int v;
	int w;
};
vector son[maxn];
struct node{
	int dis,u;
};
bool operator > (const node &a,const node& b) {
	return a.dis > b.dis;
}
priority_queue,greater> q;
void dijstra(int s){
	d[s] = 0;
	vis[s] = 0;
	q.push({0,s});
	while(!q.empty()){
		node t = q.top();
		q.pop();
		int u = t.u;
		if(vis[u]){
			continue;
		}
		for(int i=0;i
			int v = son[u][i].v;
			int w = son[u][i].w;
			if(d[v] > d[u] + w){
				d[v] = d[u] + w;
				q.push({d[v],v});
			}
		}
	}
}
int main(){
	int n,m;
	cin >> n >> m;
	for(int i=1;i<=m;i++){
		int u,v,w;
		cin >> u >> v >> w;
		son[u].push_back({v,w});
		son[v].push_back({u,w});
	}
	memset(d,63,sizeof(d));
	memset(vis,0,sizeof(vis));
	dijstra(1);
	cout << d[n] ;
}

//3.spfa算法
//队列写法
#include
using namespace std;
#include
#include
const int maxn = 1e6+5;
struct Edge{
	int to,next,w;
};
Edge edge[maxn];
int vis[maxn],n,m,d[maxn],cnt = 0;
int head[maxn];
queue q;
void add(int u,int v,int w){
	edge[++cnt].to = v;
	edge[cnt].next = head[u];
	edge[cnt].w = w;
	head[u] = cnt;
}
void spfa(){
	memset(vis,0,sizeof(vis));
	memset(d,0x3f,sizeof(d));
	d[1] = 0;
	vis[1] = 1;
	q.push(1);
	while(!q.empty()){
		int u = q.front();
		q.pop();
		vis[u] = 0;
		for(int i=head[u];i;i = edge[i].next){
			int v = edge[i].to;
			if( d[v] > d[u] + edge[i].w ){
				d[v] = d[u] + edge[i].w;
				if(!vis[v])   q.push(v);
			}
		}
	}
}
int main(){
	cin >> n >> m;
	for(int i=1;i<=m;i++){
		int u,v,w;
		cin >> u >> v >> w;
		add(u,v,w);
		add(v,u,w);
	}
	spfa();
	cout << d[n];
}

//4.floyd算法   只是费时间而已   
#include
#include
using namespace std;
int d[1000][1000];
int n,m;
int main(){
	cin >> n >> m;
	memset(d,0x3f,sizeof(d));
	for(int i=1;i<=n;i++){
		d[i][i] = 0;
	}
	for(int i=1;i<=m;i++){
		int u,v,w;
		scanf("%d %d %d",&u,&v,&w);
		d[u][v] = min(d[u][v],w);
	}
	for(int k=1;k<=n;k++){
		for(int i=1;i<=n;i++){
			for(int j=1;j<=n;j++){
				d[i][j] = min(d[i][j],d[i][k] + d[k][j]);
			}
		}
	}
	cout << d[1][n];
}