Submission #37939

#	Time	Username	Problem	Language	Result	Execution time	Memory
37939		patrikpavic2	SIR (COI15_sir)	C++14	0 / 100	319 ms	21980 KiB

sir

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>

#define mp make_pair
#define X first
#define Y second

using namespace std;

typedef long long llint;
typedef pair < llint,llint> pii;

const llint N = 1e5 + 500;
const llint INF = 0x3f3f3f3f;
const llint MOD = 1e9 + 7;
vector < pii > hull;
vector < pii > v2;
vector < pii > hull2,hull3;
pii P;
llint n,m,nn;

llint ccw(pii A,pii B,pii C){
    return A.X * (B.Y - C.Y) + B.X * (C.Y - A.Y) + C.X * (A.Y - B.Y);
}

llint dis(pii A,pii B){
    return (A.X - B.X) * (A.X - B.X) + (A.Y - B.Y) * (A.Y - B.Y);
}
bool cmp(pii A,pii B){
    if(A.Y == B.Y) return A.X < B.X;
    return A.Y < B.Y;
}

void convex_hull(){
    sort(v2.begin(),v2.end(),cmp);
    for(int i = 0;i<v2.size();i++){
        pii x = v2[i];
        while(hull2.size() >= 2 && ccw(hull2[hull2.size() - 1],hull2[hull2.size()-2],x) >= 0)
            hull2.pop_back();
        hull2.push_back(x);
    }
    hull2.pop_back();
    hull3 = hull2;
    hull2.clear();
    for(int i = 0;i<v2.size();i++){
        pii x = v2[i];
        while(hull2.size() >= 2 && ccw(hull2[hull2.size()-1], hull2[hull2.size() - 2],x) <= 0)
            hull2.pop_back();
        hull2.push_back(x);
    }
    for(int i = 0;i<hull2.size();i++)
        hull3.push_back(hull2[hull2.size() - i - 1]);
    hull2 = hull3;
    hull2.pop_back();
}

llint solve(){
    llint sol = 0;
    llint cur = 0;
    int j = 0,k = 0;
    for(int i = 0;i<n;i++){
        while(nn > 1 && ccw(hull[i],hull2[k],hull2[(k+1)%nn]) <= 0){
            k=(k+1)%nn;
        }
        if(i == j)
            j = (j + 1) % n;
        while(ccw(hull[i],hull[j],hull2[k]) > 0){
            cur += abs(ccw(hull[i],hull[(j-1+n)%n],hull[j]));
            j=(j+1)%n;
        }
        sol = max(sol, cur);
        if(i != j && i + 1 != j)
            cur -= abs(ccw(hull[i],hull[(i+1)%n],hull[(j-1+n)%n]));
        if(i == j)
            j = (j + 1) % n;
    }
    return sol;
}

void load(){
    scanf("%lld",&n);
    for(llint i = 0;i<n;i++){
        llint x,y;scanf("%lld%lld",&x,&y);
        hull.push_back(make_pair(x,y));
    }
    scanf("%lld",&m);
    for(llint i = 0;i<m;i++){
        llint x,y;scanf("%lld%lld",&x,&y);
        v2.push_back(make_pair(x,y));
    }
}

int main(){
    load();
    convex_hull();
    printf("%lld\n",solve());
}

Compilation message (stderr)

sir.cpp: In function 'void convex_hull()':
sir.cpp:41:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<v2.size();i++){
                    ^
sir.cpp:50:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<v2.size();i++){
                    ^
sir.cpp:56:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<hull2.size();i++)
                    ^
sir.cpp: In function 'void load()':
sir.cpp:86:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&n);
                     ^
sir.cpp:88:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         llint x,y;scanf("%lld%lld",&x,&y);
                                          ^
sir.cpp:91:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&m);
                     ^
sir.cpp:93:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         llint x,y;scanf("%lld%lld",&x,&y);
                                          ^

• Subtask 1: 0 / 12
• Subtask 2: 0 / 39
• Subtask 3: 0 / 49