Submission #947975

#	Time	Username	Problem	Language	Result	Execution time	Memory
947975		PM1	Stove (JOI18_stove)	C++17	100 / 100	74 ms	8856 KiB

stove

#include <bits/stdc++.h>
using namespace std;
const int mxn=1e5+5;
#define fr first
#define sc second
int n,k,a[mxn],nxt[mxn],pre[mxn],par[mxn],sz[mxn],L[mxn],R[mxn],ans;
set<pair<int,int>>s;
int fndpar(int x){
	return (par[x]==x)?x:par[x]=fndpar(par[x]);
}
void dsu(int x,int y){
	ans+=L[y]-R[x];
	
	int z=pre[x],zz=nxt[y],w=L[x],ww=R[y];
	if(y!=n){
		int d=L[fndpar(nxt[y])]-R[y];
		s.erase({d,y});
	}
	if(sz[x]<sz[y])swap(x,y);
	par[y]=x;
	sz[x]+=sz[y];
	L[x]=w;
	R[x]=ww;
	pre[x]=z;
	nxt[x]=zz;
	if(y!=n){
		int d=L[fndpar(nxt[x])]-R[x];
		s.erase({d,x});
	}
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		nxt[i]=i+1;
		pre[i]=i-1;
		par[i]=i;
		sz[i]=1;
		L[i]=a[i];
		R[i]=a[i]+1;
		ans++;
	}
	for(int i=1;i<n;i++){
		s.insert({a[i+1]-a[i],i});
	}
	while(s.size()>=k){
		auto xxx=*s.begin();
		int x=fndpar(xxx.sc),y=fndpar(nxt[x]);
		s.erase(xxx);
		dsu(x,y);

	}
	cout<<ans;
	return 0;
}

Compilation message (stderr)

stove.cpp: In function 'int main()':
stove.cpp:49:16: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   49 |  while(s.size()>=k){
      |        ~~~~~~~~^~~

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 50 / 50