Submission #261937

#	Time	Username	Problem	Language	Result	Execution time	Memory
261937		errorgorn	Climbers (RMI18_climbers)	C++14	5 / 100	241 ms	392696 KiB

climbers

//雪花飄飄北風嘯嘯
//天地一片蒼茫

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl;

#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

int n;
ll arr[5005];
ll memo[5005][5005][2];

ll dp(int l,int r,int flag){
	//cerr<<l<<" "<<r<<" "<<flag<<endl;
	if (memo[l][r][flag]!=-1) return memo[l][r][flag];
	
	memo[l][r][flag]=1e18;
	
	ll height;
	if (flag==0) height=arr[l];
	else height=arr[r];
	
	if (r-l==2){
		return memo[l][r][flag]=arr[r+l>>1]-height;
	}
	
	ll res=1e18;
	
	if (arr[l]<arr[l+1] && arr[r-1]>arr[r]){
		if (arr[l+1]<arr[r-1]) res=min(res,arr[l+1]-height+dp(l+1,r,0));
		else res=min(res,arr[r-1]-height+dp(l,r-1,1));
	}
	if (arr[l]>arr[l+1] && arr[r-1]<arr[r]){
		if (arr[l+1]>arr[r-1]) res=min(res,height-arr[l+1]+dp(l+1,r,0));
		else res=min(res,height-arr[r-1]+dp(l,r-1,1));
	}
	if (flag==0){
		if (arr[l]<arr[l+1] && arr[r-1]<arr[r]){
			if (arr[l+1]<arr[r]) res=min(res,arr[l+1]-height+dp(l+1,r,0));
			else res=min(res,arr[r-1]-height+dp(l,r,1));
		}
		if (arr[l]>arr[l+1] && arr[r-1]>arr[r]){
			if (arr[l+1]>arr[r]) res=min(res,height-arr[l+1]+dp(l+1,r,0));
			else res=min(res,height-arr[r-1]+dp(l,r,1));
		}
	}
	if (flag==1){
		if (arr[l]<arr[l+1] && arr[r-1]<arr[r]){
			if (arr[l]<arr[r-1]) res=min(res,height-arr[r-1]+dp(l,r-1,1));
			else res=min(res,height-arr[l+1]+dp(l,r,0));
		}
		if (arr[l]>arr[l+1] && arr[r-1]>arr[r]){
			if (arr[l]>arr[r-1]) res=min(res,arr[r-1]-height+dp(l,r-1,1));
			else res=min(res,arr[l+1]-height+dp(l,r,0));
		}
	}
	
	
	return memo[l][r][flag]=res;
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	memset(memo,-1,sizeof(memo));
	
	cin>>n;
	rep(x,0,n) cin>>arr[x];
	
	cout<<dp(0,n-1,0);
}

Compilation message (stderr)

climbers.cpp: In function 'long long int dp(int, int, int)':
climbers.cpp:43:32: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   return memo[l][r][flag]=arr[r+l>>1]-height;
                               ~^~

• Subtask 1: 0 / 25
• Subtask 2: 5 / 25
• Subtask 3: 0 / 50