Submission #831965

#	Time	Username	Problem	Language	Result	Execution time	Memory
831965		DarkMatter	Lightning Rod (NOI18_lightningrod)	C++14	100 / 100	1558 ms	262144 KiB

Main

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include<unordered_map>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int>pi;
typedef pair<ll, ll>pl;
typedef vector<pi>vpi;
typedef vector<pl>vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<bool> vb;
const long double PI = acos(-1);
const ll oo = 1e18;
const int MOD = 1e9 + 7;
const int N = 2e5 + 7;
#define endl '\n'
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define read(v) for (auto& it : v) scanf("%d", &it);
#define readL(v) for (auto& it : v) scanf("%lld", &it);
#define print(v) for (auto it : v) printf("%d ", it); puts("");
#define printL(v) for (auto it : v) printf("%lld ", it); puts("");
void solve() {
	ll n, ans = 0;
	scanf("%lld", &n);
	vl pref(n), suf(n);
	for (int i = 0; i < n; i++) {
		ll x, y;
		scanf("%lld %lld", &x, &y);
		ll sum = x + y, dif = y - x;
		suf[i] = dif;
		pref[i] = max(sum, !i ? 0 : pref[i - 1]);
	}
	for (int i = n - 1; i >= 0; i--) {
		ans += (!i || pref[i] > pref[i - 1]) && ((i == n - 1) || suf[i] > suf[i + 1]);
		if (i != n - 1)
			suf[i] = max(suf[i], suf[i + 1]);
	}
	printf("%lld\n", ans);
}
int t = 1;
int main() {
	//#ifndef ONLINE_JUDGE
	//	freopen("input.txt", "r", stdin);
	//#endif
		//scanf("%d", &t);
	while (t--) solve();
}

Compilation message (stderr)

lightningrod.cpp: In function 'void solve()':
lightningrod.cpp:30:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |  scanf("%lld", &n);
      |  ~~~~~^~~~~~~~~~~~
lightningrod.cpp:34:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |   scanf("%lld %lld", &x, &y);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 26 / 26
• Subtask 6: 10 / 10
• Subtask 7: 20 / 20