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답안 #196853

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
196853 2020-01-17T09:55:06 Z balbit Fences (JOI18_fences) C++14
100 / 100
 21 ms 1144 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define ull unsigned ll
#define f first
#define s second
#define FOR(i,a,b) for (int i=(a); i<(b); ++i)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) for (int i=(n-1); i>=0; --i)
#define REP1(i,n) FOR(i,1,n+1)
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
#define SQ(x) (x)*(x)
#define MN(a,b) a = min(a,(__typeof__(a))(b))
#define MX(a,b) a = max(a,(__typeof__(a))(b))
#define pb push_back
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#ifdef BALBIT
#define IOS()
#define bug(...) fprintf(stderr,"#%d (%s) = ",__LINE__,#__VA_ARGS__),_do(__VA_ARGS__);
template<typename T> void _do(T &&x){cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T &&x, S &&...y){cerr<<x<<", ";_do(y...);}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define bug(...)
#endif

const int iinf = 1<<29;
const ll inf = 1ll<<60;
const ll mod = 1e9+7;


void GG(){cout<<"-1\n"; exit(0);}

ll mpow(ll a, ll n, ll mo = mod){ // a^n % mod
    ll re=1;
    while (n>0){
        if (n&1) re = re*a %mo;
        a = a*a %mo;
        n>>=1;
    }
    return re;
}

ll inv (ll b, ll mo = mod){
    if (b==1) return b;
    return (mo-mo/b) * inv(mo%b) % mo;
}

const int maxn = 1e5+5;

struct pt{
	double x, y;
	bool operator < (const pt &b) const {
		return tie(x,y) < tie(b.x,b.y);
	}
	pt operator + (const pt &b) const {
		return {x+b.x,y+b.y};
	}
	pt operator - (const pt &b) const {
		return {x-b.x,y-b.y};
	}
	pt operator * (const double d) const {
		return {x*d,y*d};
	}
	pt operator / (const double d) const {
		return {x/d,y/d};
	}
	double operator * (const pt &b) const {
		return x*b.x + y*b.y;
	}
	double operator ^ (const pt &b) const { // Cross!
		return x*b.y - y*b.x;
	}
	double len() {
        return hypot(x,y);
	}
	pt(double xx=0, double yy=0): x(xx), y(yy){  }
};

struct line{
    pt a, b, ab; // start and end points
    line(pt _a, pt _b) {
        a=_a; b=_b; ab = b-a;
    }
    double len(){
        ab = b-a; return ab.len();
    }
    line(){}
};

double dist(pt &a, pt &b) {
    return hypot(a.x-b.x,a.y-b.y);
}

pt proj(line p, pt q) {
// Point of minimum projection
    if (p.ab.len() == 0) return p.a;
    double k = (q-p.a)*(p.ab)/(SQ(p.ab.x) + SQ(p.ab.y)); // scaled factor of p
    if (k<=0) return p.a; // on left
    if (k >= 1) return p.b; // on right
    return p.a + p.ab * k;
}
const double eps = 1e-7;

line wall[5];

const int MX = 4*200 + 8 + 10;

double d[MX][MX][2]; // Id 1, Id 2, parity
line fen[MX];

bool its(line p, line q) {
    return ((q.a-p.a) ^ p.ab) * ((q.b-p.a) ^ p.ab) < 0 &&
            ((p.a-q.a) ^ q.ab) * ((p.b-q.a) ^ q.ab) < 0;
    // If the ends of q are on different sides (opposite cross signs of p) and same applies for p
    // Strictly less: touching is acceptable in case fence goes along the wall
}

bool ok(line p) {
    REP(i,5) if (its(p,wall[i])) return 0;
    return 1;
}

double dinf = 1e10;

line CUT = {{0,0},{1,7*11*13}};

signed main(){
    IOS();


    int n, s; cin>>n>>s;
// Build the walls
    wall[0] = {{-s,s},{s,s}};
    wall[1] = {{s,s},{s,-s}};
    wall[2] = {{s,-s},{-s,-s}};
    wall[3] = {{-s,-s},{-s,s}};
    wall[4] = {{0,s},{0,-s}}; // To prevent diagonals of the  square from skipping to each other
    REP(i,n) {
        int a, b, c, d; cin>>a>>b>>c>>d;
        fen[i] = {{a,b},{c,d}};
    }
    REP(i,4) {
        fen[i+n] = {wall[i].a,wall[i].a}; // Dummy lines for corners
    }

    bug((proj(fen[2],fen[3].a)-fen[3].a).len());

    n+=4;

    REP(i,n) REP(j,n) REP(k,2){
        if (i==j && k==0) d[i][j][k] = 0;
        else {
            bool IJ = its(CUT,{fen[i].a, fen[j].a});
            bool B;
// Assume the person is sitting at a for each fence
            d[i][j][0]=d[i][j][1]=1e10;
            line to;
//            bug(d[i][j][B]);
            to = {fen[i].a,proj(fen[j],fen[i].a)};
            B = its(CUT,to) ^ its(CUT,line(fen[j].a,to.b));
            if (ok(to)) MN(d[i][j][B],to.len() );
            // First project from fen[i].a to fen[j], then walk back to fen[j].a

            to = {fen[i].b,proj(fen[j],fen[i].b)};
            B = its(CUT,to)^its(CUT,fen[i])^its(CUT,line(fen[j].a,to.b));
            if (ok(to)) MN(d[i][j][B],to.len());

            to = {fen[j].a,proj(fen[i],fen[j].a)};
            B = its(CUT,to)^its(CUT,line(fen[i].a,to.b));
            if (ok(to)) MN(d[i][j][B],to.len() );

            to = {fen[j].b,proj(fen[i],fen[j].b)};
            B = its(CUT,to)^its(CUT,fen[j])^its(CUT,line(fen[i].a,to.b));
            if (ok(to)) MN(d[i][j][B],to.len() );


            MN(d[j][i][0], d[i][j][0]); // It's the same going backwards
            MN(d[j][i][1], d[i][j][1]);
            bug(i,j,d[i][j][0],d[i][j][1]);
        }
    }

    REP(k,n) REP(i,n) REP(j,n) REP(b1,2) REP(b2,2){
        MN(d[i][j][b1^b2],d[i][k][b1] + d[k][j][b2]); // Floyd Warshall
    }
    bug("NOEFNOW");
    double re = 1e10;
    REP(i,n) REP(j,n) REP(k,2){
        MN(re, d[i][i][1]);
        bug(i,j,k,d[i][j][k]);
    }
    cout<<re<<endl;
}

Compilation message

fences.cpp: In function 'int main()':
fences.cpp:137:17: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[0] = {{-s,s},{s,s}};
                 ^
fences.cpp:137:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[0] = {{-s,s},{s,s}};
                            ^
fences.cpp:137:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:137:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:138:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[1] = {{s,s},{s,-s}};
                            ^
fences.cpp:138:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:138:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:138:25: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[1] = {{s,s},{s,-s}};
                         ^
fences.cpp:139:30: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[2] = {{s,-s},{-s,-s}};
                              ^
fences.cpp:139:19: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[2] = {{s,-s},{-s,-s}};
                   ^
fences.cpp:139:24: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[2] = {{s,-s},{-s,-s}};
                        ^
fences.cpp:139:27: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[2] = {{s,-s},{-s,-s}};
                           ^
fences.cpp:140:17: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[3] = {{-s,-s},{-s,s}};
                 ^
fences.cpp:140:20: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[3] = {{-s,-s},{-s,s}};
                    ^
fences.cpp:140:25: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[3] = {{-s,-s},{-s,s}};
                         ^
fences.cpp:140:30: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[3] = {{-s,-s},{-s,s}};
                              ^
fences.cpp:141:28: warning: narrowing conversion of 'second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[4] = {{0,s},{0,-s}}; // To prevent diagonals of the  square from skipping to each other
                            ^
fences.cpp:141:25: warning: narrowing conversion of '- second' from 'int' to 'double' inside { } [-Wnarrowing]
     wall[4] = {{0,s},{0,-s}}; // To prevent diagonals of the  square from skipping to each other
                         ^
fences.cpp:144:30: warning: narrowing conversion of 'a' from 'int' to 'double' inside { } [-Wnarrowing]
         fen[i] = {{a,b},{c,d}};
                              ^
fences.cpp:144:30: warning: narrowing conversion of 'b' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:144:30: warning: narrowing conversion of 'c' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:144:30: warning: narrowing conversion of 'd' from 'int' to 'double' inside { } [-Wnarrowing]
fences.cpp:157:18: warning: unused variable 'IJ' [-Wunused-variable]
             bool IJ = its(CUT,{fen[i].a, fen[j].a});
                  ^~

Subtask #1
18.0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 380 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 3 ms 464 KB Output is correct
15 Correct 2 ms 376 KB Output is correct
16 Correct 2 ms 376 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 376 KB Output is correct
20 Correct 1 ms 376 KB Output is correct

Subtask #2
33.0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 380 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 3 ms 464 KB Output is correct
15 Correct 2 ms 376 KB Output is correct
16 Correct 2 ms 376 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 376 KB Output is correct
20 Correct 1 ms 376 KB Output is correct
21 Correct 2 ms 376 KB Output is correct
22 Correct 2 ms 376 KB Output is correct
23 Correct 3 ms 376 KB Output is correct
24 Correct 2 ms 504 KB Output is correct
25 Correct 2 ms 376 KB Output is correct
26 Correct 2 ms 376 KB Output is correct
27 Correct 2 ms 376 KB Output is correct
28 Correct 3 ms 504 KB Output is correct
29 Correct 2 ms 388 KB Output is correct
30 Correct 16 ms 376 KB Output is correct
31 Correct 3 ms 376 KB Output is correct
32 Correct 3 ms 376 KB Output is correct
33 Correct 2 ms 376 KB Output is correct
34 Correct 2 ms 376 KB Output is correct
35 Correct 2 ms 376 KB Output is correct
36 Correct 2 ms 376 KB Output is correct
37 Correct 2 ms 376 KB Output is correct
38 Correct 2 ms 376 KB Output is correct
39 Correct 2 ms 376 KB Output is correct
40 Correct 2 ms 376 KB Output is correct
41 Correct 2 ms 376 KB Output is correct
42 Correct 3 ms 376 KB Output is correct
43 Correct 3 ms 504 KB Output is correct

Subtask #3
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 380 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 3 ms 464 KB Output is correct
15 Correct 2 ms 376 KB Output is correct
16 Correct 2 ms 376 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 376 KB Output is correct
20 Correct 1 ms 376 KB Output is correct
21 Correct 2 ms 376 KB Output is correct
22 Correct 2 ms 376 KB Output is correct
23 Correct 3 ms 376 KB Output is correct
24 Correct 2 ms 504 KB Output is correct
25 Correct 2 ms 376 KB Output is correct
26 Correct 2 ms 376 KB Output is correct
27 Correct 2 ms 376 KB Output is correct
28 Correct 3 ms 504 KB Output is correct
29 Correct 2 ms 388 KB Output is correct
30 Correct 16 ms 376 KB Output is correct
31 Correct 3 ms 376 KB Output is correct
32 Correct 3 ms 376 KB Output is correct
33 Correct 2 ms 376 KB Output is correct
34 Correct 2 ms 376 KB Output is correct
35 Correct 2 ms 376 KB Output is correct
36 Correct 2 ms 376 KB Output is correct
37 Correct 2 ms 376 KB Output is correct
38 Correct 2 ms 376 KB Output is correct
39 Correct 2 ms 376 KB Output is correct
40 Correct 2 ms 376 KB Output is correct
41 Correct 2 ms 376 KB Output is correct
42 Correct 3 ms 376 KB Output is correct
43 Correct 3 ms 504 KB Output is correct
44 Correct 21 ms 888 KB Output is correct
45 Correct 19 ms 888 KB Output is correct
46 Correct 18 ms 1016 KB Output is correct
47 Correct 17 ms 1016 KB Output is correct
48 Correct 19 ms 920 KB Output is correct
49 Correct 19 ms 892 KB Output is correct
50 Correct 18 ms 888 KB Output is correct
51 Correct 17 ms 888 KB Output is correct
52 Correct 19 ms 888 KB Output is correct
53 Correct 19 ms 888 KB Output is correct
54 Correct 19 ms 924 KB Output is correct
55 Correct 19 ms 1016 KB Output is correct
56 Correct 19 ms 888 KB Output is correct
57 Correct 18 ms 1016 KB Output is correct
58 Correct 18 ms 1016 KB Output is correct
59 Correct 18 ms 1016 KB Output is correct
60 Correct 18 ms 1016 KB Output is correct
61 Correct 18 ms 1144 KB Output is correct
62 Correct 2 ms 504 KB Output is correct
63 Correct 3 ms 508 KB Output is correct
64 Correct 15 ms 1016 KB Output is correct
65 Correct 17 ms 1016 KB Output is correct
66 Correct 15 ms 1144 KB Output is correct
67 Correct 16 ms 888 KB Output is correct
68 Correct 16 ms 888 KB Output is correct
69 Correct 18 ms 888 KB Output is correct
70 Correct 16 ms 888 KB Output is correct
71 Correct 17 ms 888 KB Output is correct
72 Correct 17 ms 888 KB Output is correct