蓝桥杯刷题 - 技术栈

P8802 [蓝桥杯 2022 国 B] 出差（迪杰斯特拉）

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
int n, m;
const int N = 1010, M = 2 * 10010;
int a[N];
bool st[N]; 
int h[N], e[M], ne[M], w[M], idx;
void add(int a, int b, int c){
	e[idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx++;
}
int dist[N];
typedef pair<int, int>PII;
int dijkstra(){
	memset(dist, 0x3f, sizeof(dist));
	dist[1] = 0;
	priority_queue<PII, vector<PII>, greater<PII> > heap;
	heap.push({0, 1});
	while(heap.size()){
		auto t = heap.top();
		heap.pop();
		int ver = t.second, distance = t.first;
		if(st[ver])continue;
		st[ver] = true;
		for(int i = h[ver]; i != -1; i = ne[i]){
			int j = e[i];
			int distt = w[i] + distance; 
			if(j != n)distt += a[j];
			if(dist[j] > distt){
				dist[j] = distt;
				heap.push({dist[j], j});
			}
		}
	}
	if(dist[n] == 0x3f3f3f3f)return -1;
	else return dist[n];
}
signed main()
{
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m;
	memset(h, -1, sizeof(h));
	for(int i = 1; i <= n; i++)cin >> a[i];
	for(int i = 1; i <= m; i++){
		int u, v, c; cin >> u >> v >> c;
		add(u, v, c);
		add(v, u, c); 
	}
	int t = dijkstra();
	cout << t << endl;
    
    return 0;
}

P8799 [蓝桥杯 2022 国 B] 齿轮

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
int n, q;
const int N = 200010;
int a[N], ans[N], mp[N];
int flag;
signed main()
{
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> q;
	for(int i = 1; i <= n; i++){
		cin >> a[i];
		mp[a[i]]++;
	}
	sort(a + 1, a + n + 1);
	for(int i = 1; i <= n; i++){
		if(i > 1 && a[i] == a[i - 1]){
			flag = 1;
			continue;
		}
		for(int j = a[i]; j <= a[n]; j += a[i]){
			if(mp[j]){
				ans[j / a[i]] = 1;
			}
		}
	}
	
	while(q--){
		int x; cin >> x;
		if(x == 1){
			if(flag)cout << "YES" << endl;
			else cout << "NO" << endl;
			continue;
		}
		if(ans[x])cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	
    
    return 0;
}

P9428 [蓝桥杯 2023 国 B] 逃跑

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
int n, m;
const int N = 1000010;
double p, ans, dp[N];
int flag[N];//跳点 
struct node{
	int h, ne, e;
};
int h[N], ne[N << 1], e[N << 1], idx;
void add(int a, int b){
	e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}
void dfs(int u, int fa, double pp){
	if(flag[fa])pp *= p;
	if(u != 1){
		if(flag[fa])dp[u] = dp[fa] + 1;
		else dp[u] = dp[fa] + pp;
	}
	ans += dp[u];
	for(int i = h[u]; i != -1; i = ne[i]){
		int j = e[i];
		if(j == fa)continue;
		dfs(j, u, pp);
	}
	pp /= p;
}
signed main()
{
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m >> p;
	memset(h, -1, sizeof(h)); 
	for(int i = 1; i < n; i++){
		int u, v; cin >> u >> v;
		add(u, v), add(v, u);
	} 
	for(int i = 1; i <= m; i++){
		int u; cin >> u;
		flag[u] = true;
	}
	dfs(1, 0, 1);
	cout << fixed << setprecision(2) << ans / n << endl;
    
    return 0;
}

P8804 [蓝桥杯 2022 国 B] 故障

注意比较doule时候精度丢失

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
int n, m, k;
const int N = 520;
double a[N], dp[N];
double b[N][N];
bool st[N];
struct node{
	int id;
	double ans;
}no[N];
bool cmp(node a, node b){
	if(fabs(a.ans - b.ans) > 1e-6)return a.ans > b.ans;
	return a.id < b.id;
}
signed main(){
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m;
	for(int i = 1; i <= n; i++)cin >> a[i];
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= m; j++){
			double x; cin >> x;
			b[i][j] = x / 100;
		}
	}
	cin >> k;
	while(k--){
		int x; cin >> x;
		st[x] = true;
	}
	for(int i = 1; i <= n; i++){
		dp[i] = a[i];
		for(int j = 1; j <= m; j++){
			if(st[j])dp[i] *= b[i][j];
			else dp[i] *= (1 - b[i][j]);
		}
	}
	double sum = 0;
	for(int i = 1; i <= n; i++)sum += dp[i];
	for(int i = 1; i <= n; i++){
		no[i].id = i;
		no[i].ans = dp[i] * 100 / sum;
	}
	sort(no + 1, no + n + 1, cmp);
	for(int i = 1; i <= n; i++){
		cout << no[i].id << " " << fixed << setprecision(2) << no[i].ans << endl;
	}
	
	
	return 0;
}

P8800 [蓝桥杯 2022 国 B] 卡牌

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int N = 200010;
int n, m;
struct node{
	int a, b;
}no[N];
int maxx, minn = 1e18;
bool cmp(node a, node b){
	if(a.a != b.a)return a.a < b.a;
	return a.b < b.b;
}
bool check(int x){
	int sum = 0;
	for(int i = 1; no[i].a < x && i <= n; i++){
		if(x - no[i].a <= no[i].b){
			sum += x - no[i].a;
		}
		else return false;
	}
	if(sum <= m)return true;
	return false;
}
signed main(){
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m;
	for(int i = 1; i <= n; i++)cin >> no[i].a;
	for(int i = 1; i <= n; i++){
		cin >> no[i].b;
		minn = min(minn, no[i].a);
		maxx = max(maxx,  no[i].b + no[i].a);
	}
	sort(no + 1, no + n + 1, cmp);
	int l = minn - 1, r = maxx + 1;
	while(l + 1 != r){
		int mid = l + r >> 1;
		if(check(mid))l = mid;
		else r = mid;
	}
	cout << l << endl;
	
	return 0;
}

P8806 [蓝桥杯 2022 国 B] 搬砖

cpp 复制代码

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int N = 200010;
int dp[N];
struct node{
	int w, v;
}no[N];
int n;
bool cmp(node a, node b){
	return a.v + a.w < b.v + b.w;
}
signed main(){
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n;
	for(int i = 1; i <= n; i++)cin >> no[i].w >> no[i].v;
	sort(no + 1, no + n + 1, cmp);
	int ans = 0;
	for(int i = 1; i <= n; i++){
		for(int j = no[i].v + no[i].w; j >= no[i].w; j--){
			dp[j] = max(dp[j], dp[j - no[i].w] + no[i].v);
			ans = max(ans, dp[j]);
		}
	}
	cout << ans << endl;
	
	return 0;
}