oj.uz

Submission #538975

# Submission time Handle Problem Language Result Execution time Memory
538975 2022-03-18T06:31:34 Z jamielim Planine (COCI21_planine) C++14
110 / 110
 275 ms 37744 KB 
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb emplace_back
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
typedef long long ll;
typedef pair<int,int> ii;
typedef pair<ii,ii> i4;
const int MOD=1000000007;
const int INF=1012345678;
const ll LLINF=1012345678012345678LL;
const double PI=3.1415926536;
//const double EPS=1e-14;
const double EPS=1e-10;

const int maxn=1000005;
int n,h;
int x[maxn],y[maxn];
double le[maxn];
pair<double,double> range[maxn]; // right, left
int num=0;

struct ch{
	vector<ii> v;
	void add(int i){ // add the point of index i
		while(SZ(v)>=2){
			ii a=v[SZ(v)-2],b=mp(x[i],y[i]);
			double m=(double)(b.se-a.se)/(double)(b.fi-a.fi);
			double c=(double)b.se-m*(double)(b.fi);
			if(v.back().se<EPS+m*(double)(v.back().fi)+c)v.pop_back();
			else break;
		}
		v.pb(x[i],y[i]);
	}
	double qry(){ // intersection of the most recent line with y=h
		if(SZ(v)<2)return INF;
		ii a=v[SZ(v)-2],b=v.back();
		double m=(double)(b.se-a.se)/(double)(b.fi-a.fi);
		double c=(double)b.se-m*(double)(b.fi);
		return ((double)(h)-c)/m;
	}
}fwd,bwd;

int main(){
	scanf("%d%d",&n,&h);
	for(int i=0;i<n;i++){
		scanf("%d%d",&x[i],&y[i]);
	}
	for(int i=0;i<n-1;i++){
		fwd.add(i);
		if(i%2==0&&i>0)le[i]=fwd.qry();
	}
	for(int i=n-1;i>0;i--){
		bwd.add(i);
		if(i%2==0&&i<n-1){
			range[num++]=mp(bwd.qry(),le[i]);
			//printf("%f %f\n",range[num-1].fi,range[num-1].se);
		}
	}
	sort(range,range+num);
	double prv=-INF;
	int ctr=0;
	for(int i=0;i<num;i++){
		if(prv+EPS>=range[i].se){
			continue;
		}
		prv=range[i].fi;
		ctr++;
	}
	printf("%d",ctr);
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:49:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |  scanf("%d%d",&n,&h);
      |  ~~~~~^~~~~~~~~~~~~~
Main.cpp:51:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |   scanf("%d%d",&x[i],&y[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 3 ms 644 KB Output is correct
3 Correct 3 ms 704 KB Output is correct
4 Correct 21 ms 3660 KB Output is correct
5 Correct 24 ms 3788 KB Output is correct
6 Correct 26 ms 3980 KB Output is correct
7 Correct 240 ms 33700 KB Output is correct
8 Correct 226 ms 35768 KB Output is correct
9 Correct 263 ms 37744 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 280 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 308 KB Output is correct
6 Correct 1 ms 324 KB Output is correct
7 Correct 1 ms 340 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 3 ms 644 KB Output is correct
3 Correct 3 ms 704 KB Output is correct
4 Correct 21 ms 3660 KB Output is correct
5 Correct 24 ms 3788 KB Output is correct
6 Correct 26 ms 3980 KB Output is correct
7 Correct 240 ms 33700 KB Output is correct
8 Correct 226 ms 35768 KB Output is correct
9 Correct 263 ms 37744 KB Output is correct
10 Correct 1 ms 280 KB Output is correct
11 Correct 2 ms 356 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 308 KB Output is correct
15 Correct 1 ms 324 KB Output is correct
16 Correct 1 ms 340 KB Output is correct
17 Correct 242 ms 34772 KB Output is correct
18 Correct 275 ms 34604 KB Output is correct
19 Correct 23 ms 3660 KB Output is correct
20 Correct 237 ms 33744 KB Output is correct
21 Correct 25 ms 3660 KB Output is correct
22 Correct 259 ms 37504 KB Output is correct
23 Correct 1 ms 340 KB Output is correct
24 Correct 236 ms 36784 KB Output is correct
25 Correct 26 ms 3740 KB Output is correct
26 Correct 271 ms 37708 KB Output is correct
27 Correct 12 ms 1968 KB Output is correct