Submission #188231

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Source Code Expand

#define _CRT_SEURE_NO_WARNINGS

#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <iomanip>
#include <map>
#include <algorithm>
#include <numeric>
#include <set>
#include <queue>
#include <sstream>
#include <stack>
#include <cctype>
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define loop(i,a,b) for(ull i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)
#define iter(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define riter(i,c) for(auto i=(c).rbegin(); i!=(c).rend(); ++i)
#define clr(a,i) memset((a), (i) ,sizeof(a))
const double eps = 1e-10;
const double pi = acos(-1.0);
const double inf = (int)1e8;

template<typename T>ostream&operator<<(ostream&os, vector<T>const&v){
    iter(it, v) os << *it << (it + 1 == v.end() ? "" : " ");
    return os;
}
template<typename T>ostream&operator<<(ostream&os, set<T>const&v){
    iter(it, v) os << *it << (it + 1 == v.end() ? "" : " ");
    return os;
}
template<typename T, typename U>ostream&operator<<(ostream&os, map<T, U>const&v){
    iter(it, v) os << *it << (it + 1 == v.end() ? "" : " ");
    return os;
}
template<typename T, typename U>ostream&operator<<(ostream&os, const pair<T, U>&p){
    return os << "[" << p.dirst << "," << p.second << "]";
}

inline int gi(){
    int n; cin >> n;
    return n;
}

inline string gs(){
    string n; cin >> n;
    return n;
}

template<typename T>
istream& operator>>(istream& is, vector<T> &v){
    string s;
    getline(is, s);
    stringstream ss(s);
    T t;
    while (ss >> t){
        v.push_back(t);
    }
    return is;
}

inline
bool in(int x, int y, int w, int h){
    return 0 <= x && 0 <= y && x < w&&y < h;
}

int main(){
    int n, d, x, y;
    while (cin >> n >> d >> x >> y){
        double p;
        if (x%d == 0 && y%d == 0){

            const int w = 350;
            const int h = 350;

            x /= d; y /= d;
            x += w / 2; y += h / 2;

            if (!in(x, y, w, h)) p = 0;
            else {

                vvd cur(h, vd(w, 0));
                cur[h / 2][w / 2] = 1;

                int const dx[] = { 1, 0, 0, -1 };
                int const dy[] = { 0, 1, -1, 0 };

                rep(i, n){
                    vvd next(h, vd(w, 0));
                    rep(y, h)rep(x, w){
                        int nx, ny;
                        nx = x + 0;
                        ny = y + 1;
                        if (!in(nx, ny, w, h) || cur[y][x] < 1e-10) goto aaa;
                        next[ny][nx] += cur[y][x] / 4;

                    aaa:;

                        nx = x + 0;
                        ny = y + -1;
                        if (!in(nx, ny, w, h) || cur[y][x] < 1e-10) goto bbb;
                        next[ny][nx] += cur[y][x] / 4;

                    bbb:;

                        nx = x + 1;
                        ny = y + 0;
                        if (!in(nx, ny, w, h) || cur[y][x] < 1e-10) goto ccc;
                        next[ny][nx] += cur[y][x] / 4;

                    ccc:;

                        nx = x + -1;
                        ny = y + 0;
                        if (!in(nx, ny, w, h) || cur[y][x] < 1e-10) continue;
                        next[ny][nx] += cur[y][x] / 4;
                    }
                    swap(next, cur);
                }
                p = cur[x][y];
            }
        }
        else {
            p = 0;
        }

        cout << fixed << setprecision(30) << p << endl;
    }
}

Submission Info

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