2019-2020 ICPC Northwestern European Regional Programming Contest (NWERC 2019)

2019-2020 ICPC Northwestern European Regional Programming Contest (NWERC 2019)

目录

• 2019-2020 ICPC Northwestern European Regional Programming Contest (NWERC 2019)
  • I-Inverted Deck
  • G-Gnoll Hypothesis
  • F-Firetrucks Are Red

I-Inverted Deck

#include<bits/stdc++.h>
using namespace std;

const int N=1e6+10;
int n;
int v[N],v1[N];


int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;++i) scanf("%d",v+i),v1[i]=v[i];
    int rec1=0,rec2=0;
    sort(v1+1,v1+1+n);
    for(int i=1;i<=n;++i){
        if(v[i]!=v1[i]){
            rec1=i;
            break;
        }
    }
    for(int i=n;i>=1;i--){
        if(v[i]!=v1[i]){
            rec2=i;
            break;
        }
    }
    if(rec1==0 && rec2==0){
        printf("1 1
");
        return 0;
    }
    int f=0;
    for(int i=rec1;i<rec2;++i){
        if(v[i]<v[i+1]){
            f=1;
            break;
        }
    }
    if(f){
        printf("impossible
");
    }else{
        printf("%d %d
",rec1,rec2);
    }
    return 0;
}

G-Gnoll Hypothesis

#include<bits/stdc++.h>
using namespace std;

const int N = 1010;
int n, k;
long double s[N], sum[N];

int main()
{
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    //scanf("%d%d", &n, &k);
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) {
        //scanf("%lf", s + i);
        cin >> s[i];
        s[i + n] = s[i];
    }
    if (n == k) {
        for (int i = 1; i <= n; ++i) printf("%.12Lf ", s[i]);
        return 0;
    }
    if (k == 1) {
        long double ss = 100.0;
        for (int i = 1; i <= n; ++i) printf("%.12Lf ", ss / ((long double)n));
        return 0;
    }
    for (int i = 1; i <= 2 * n; ++i) sum[i] = sum[i - 1] + s[i];
    long double t = 1.0;
    for (long double i = k, j = n; i >= 1; --i, --j) {
        t *= (j / i);
    }
    //double t1=0;
    long double t2 = 1.0;
    for (long double i = n - k, j = n - 2; i >= 1; --i, --j) t2 *= (j / i);
    for (int i = 1; i <= n; ++i) {
        long double tmpAns = 0.0, tmp = t2;
        for (int j = 1; j <= (n - k + 1); ++j) {
            if (j == (n - k + 1)) {
                tmpAns += (long double)(sum[n + i] - sum[n + i - j]);
                break;
            }
            tmpAns += (long double)(tmp * (sum[n + i] - sum[n + i - j]));
            tmp *= (long double)(((n - k - j + 1) * 1.0) / ((n - j - 1) * 1.0));
        }
        printf("%.12Lf ", tmpAns / t);
    }
    return 0;
}

F-Firetrucks Are Red

#include<bits/stdc++.h>
using namespace std;
 
const int N = 2e5 + 10;
int n, m;
int fa[N];
map<int, vector<int>>mp;
struct edge {
    int v, w;
};
vector<edge>e[N];
 
int find(int x)
{
    if (x == fa[x]) return x;
    return fa[x] = find(fa[x]);
}
 
struct node {
    int u, v, w;
};
queue<node>q;
 
// void solve(int u)
// {
//     int len = e[u].size();
//     for (int i = 0; i < len; ++i) {
//         int v = e[u][i].v, w = e[u][i].w;
//         int x = find(u);
//         int y = find(v);
//         if (x == y) continue;
//         fa[x] = y;
//         q.push(node{ u,v,w });
//         solve(v);
//     }
// }
 
bool checkF(int u, int v)
{
    int x=find(u);
    int y=find(v);
    if(x==y)
        return  false;
    else{
        fa[x]=y;
        return true;
    }
}
 
 
int main()
{
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i) {
        fa[i] = i;
        scanf("%d", &m);
        for (int j = 0; j < m; ++j) {
            int t;
            scanf("%d", &t);
            mp[t].push_back(i);
            // if (mp[t].empty()) {
            //     mp[t].push_back(i);
            // }
            // else {
            //     int len = mp[t].size();
            //     for (int k = 0; k < len; ++k) {
            //         e[i].push_back(edge{ mp[t][k],t });
            //         e[mp[t][k]].push_back(edge{ i,t });
            //         mp[t].push_back(i);
            //     }
            // }
        }
    }
    // mp.clear();
    // solve(1); 
    // if (q.size() != n - 1) {
    //     printf("impossible
");
    //     return 0;
    // }
    // while (!q.empty()) {
    //     printf("%d %d %d
", q.front().u, q.front().v, q.front().w);
    //     q.pop();
    // }
    for(auto i : mp){
        for(int j=0;j<i.second.size()-1;++j){
            if(checkF(i.second[j],i.second[j+1]))
                q.push(node{i.second[j],i.second[j+1],i.first});
        }
    }
    if (q.size() != n - 1) {
        printf("impossible
");
        return 0;
    }
    while (!q.empty()) {
        printf("%d %d %d
", q.front().u, q.front().v, q.front().w);
        q.pop();
    }
    return  0;
}