Submission #520028

#	Time	Username	Problem	Language	Result	Execution time	Memory
520028		sumit_kk10	Lightning Rod (NOI18_lightningrod)	C++17	100 / 100	912 ms	262144 KiB

Main

#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL)
#define pb push_back
#define ll long long
#define F first 
#define S second
using namespace std;
const int N = 1e7 + 5, MOD = 1e9 + 7;

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;
}

void solve(){
	int n = readInt();
	pair<int, int> a[n];
	for(int i = 0; i < n; ++i){
		a[i].F = readInt();
		a[i].S = readInt();
	}
	sort(a, a + n);
	int pre_max[n], suf_mn[n + 1];
	pre_max[0] = a[0].F + a[0].S;
	for(int i = 1; i < n; ++i)
	    pre_max[i] = max(pre_max[i - 1], a[i].F + a[i].S);
	suf_mn[n - 1] = a[n - 1].F - a[n - 1].S;
	for(int i = n - 2; i >= 0; --i)
	    suf_mn[i] = min(suf_mn[i + 1], a[i].F - a[i].S);
	int ans = (suf_mn[1] > (a[0].F - a[0].S));
	suf_mn[n] = INT_MAX;
	for(int i = 1; i < n; ++i){
	    if((pre_max[i - 1] >= (a[i].F + a[i].S)) or (suf_mn[i + 1] <= (a[i].F - a[i].S))) 
	        continue;
	    ++ans;
	}
	cout << ans << '\n';
}
 
int main(){
	fast;
	int t = 1;
	// cin >> t;
	while(t--)
		solve();
}

• 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