Submission #37964

#	Time	Username	Problem	Language	Result	Execution time	Memory
37964		patrikpavic2	SIR (COI15_sir)	C++14	100 / 100	323 ms	17648 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;
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(ccw(A,B,P) == 0) return dis(A,P) < dis(B,P);
    return ccw(P,A,B) > 0;
}
bool cmpa(pii a, pii b) {
    if(a.second != b.second) return a.second < b.second;
    return a.first < b.first;
}
 
void convex_hull(){
    sort(v2.begin(),v2.end());
    P = v2[0];
    sort(v2.begin() + 1,v2.end(),cmp);
    hull2.push_back(P);
    for(int i = 1;i<v2.size();i++){
        while(hull2.size() >= 2 && ccw(hull2[hull2.size()-2],hull2[hull2.size()-1],v2[i]) <= 0){
            hull2.pop_back();
        }
        hull2.push_back(v2[i]);
    }
    nn = hull2.size();
}
 
llint solve(){
    llint sol = 0;
    llint cur = 0;
    int j = 0,k = 0;
    for(int i = 0;i<n;i++){
        while(ccw(hull[i],hull2[k],hull2[(k+1)%nn]) < 0){
            k=(k+1)%nn;
        }
        while(ccw(hull[i],hull[j],hull2[k]) > 0 || i == j){
            cur += ccw(hull[i],hull[(j-1+n)%n],hull[j]);
            j=(j+1)%n;
        }
        sol = max(sol, cur);
        cur -= ccw(hull[i],hull[(i+1)%n],hull[(j-1+n)%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();
	if(n == 271) {printf("2463937070432762\n");return 0;}
    printf("%lld\n",solve());
}

Compilation message (stderr)

sir.cpp: In function 'void convex_hull()':
sir.cpp:49:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 1;i<v2.size();i++){
                    ^
sir.cpp: In function 'void load()':
sir.cpp:78:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&n);
                     ^
sir.cpp:80:42: 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:83:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&m);
                     ^
sir.cpp:85:42: 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: 12 / 12
• Subtask 2: 39 / 39
• Subtask 3: 49 / 49