Submission #704080

#	Time	Username	Problem	Language	Result	Execution time	Memory
704080		Potato3218	Global Warming (NOI13_gw)	C++17	19 / 40	339 ms	65536 KiB

gw

#include <bits/stdc++.h>
using namespace std;
#define beegspeed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define int long long
#define pvi pair<int,vector<int>>
#define f first
#define s second
#pragma GCC optimization ("Ofast")
#pragma GCC optimization("ffast-math,fno-stack-protector")
#pragma GCC optimization("unroll-loops")
#pragma GCC target ("avx2,popcnt,bmi2")

vector<int> H;
unordered_map<int,vector<int>> um;
bool submerged[1000007];
vector<pvi> mp;


inline int readInt() {
    int x = 0;
    char ch = getchar();
    while (ch < '0' || ch > '9') ch = getchar_unlocked();
    while (ch >= '0' && ch <= '9'){
		x = (x << 3) + (x << 1) + ch - '0';
		ch = getchar_unlocked();
	}
    return x;
}

signed main(){
	beegspeed
		um.reserve(300000);
	int n = readInt();
	for(int i = 0; i < n; i++){
		int h = readInt();
		H.push_back(h);
		um[h].push_back(i);
	}
	for(auto& itr: um){
		mp.push_back(itr);
	}
	sort(mp.begin(), mp.end(), greater<pvi>());
	int ans = 0, curr = 0;
	for(auto itr: mp){
		for(auto island:itr.second){
			submerged[island] = true;
			//check if neighbouring sections are unsubmerged yet
			if(island == 0){
				if(!submerged[1]){
					++curr;
				}
			}
			else if(island == n-1){
				if(!submerged[n-2]) ++curr;
			}
			else{
				int p = (!submerged[island + 1]) + (!submerged[island- 1]);
				//if both aren't submerged evaluates to 2, if one of them is submerged evaluates to 1, else it's just 0
				--p;
				curr += p;
			}
		}
		ans = max(ans, curr);
	}
	cout<<ans;
}

Compilation message (stderr)

gw.cpp:8: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    8 | #pragma GCC optimization ("Ofast")
      | 
gw.cpp:9: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    9 | #pragma GCC optimization("ffast-math,fno-stack-protector")
      | 
gw.cpp:10: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   10 | #pragma GCC optimization("unroll-loops")
      |

• Subtask 1: 6 / 6
• Subtask 2: 6 / 6
• Subtask 3: 7 / 7
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11