【CPE】一顆星選集(Part 6) | C++

What is the Probability!!

題目：https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=12&page=show_problem&problem=997

中文題目：https://zerojudge.tw/ShowProblem?problemid=e510

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;

int main() {
    int S, N, K;
    double p;
    cin >> S;
    while (S--) {
        cin >> N >> p >> K;
        if (p == 0) {
            cout << "0.0000\n";
            continue;
        }
        double first = pow(1.0 - p, K-1) * p;
        double r = pow(1.0 - p, N);
        cout << fixed << setprecision(4) << first / (1.0 - r) << "\n";
    }
    return 0;
}​

The Hotel with Infinite Rooms

中文題目：https://zerojudge.tw/ShowProblem?problemid=e555

#include <iostream>
using namespace std;

int main() {
    long long S, D, cnt;
    while (cin >> S >> D) {
        cnt = S;
        D -= S;
        while (D > 0) {
            cnt++;
            D -= cnt;
        }
        cout << cnt << "\n";
    }
    return 0;
}​

498-bis

題目：https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=14&page=show_problem&problem=1209#google_vignette

#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <algorithm>
using namespace std;

string s;
int x;
vector<int> v;

int main() {
    while (cin >> x) {
        getline(cin, s);
        getline(cin, s);
        stringstream ss(s);
        v.clear();
        while (ss >> s) {
            v.push_back(stoi(s));
        }
        v.pop_back();
        reverse(v.begin(), v.end());
        long long mul = 1;
        int ans = 0;
        for (int i=0; i<v.size(); i++) {
            ans += v[i]*(i+1)*mul;
            mul *= x;
        }
        cout << ans << "\n";
    }
    return 0;
}​