Submission #141080

#	Time	Username	Problem	Language	Result	Execution time	Memory
141080		tincamatei	Lightning Rod (NOI18_lightningrod)	C++14	100 / 100	639 ms	188208 KiB

Main

#include <bits/stdc++.h>

const int BUFF = 1 << 12;
const int MAX_N = 10000000;

int cursor = BUFF - 1;
char buff[BUFF];

char getChar(FILE *fin) {
	cursor++;
	if(cursor == BUFF) {
		cursor = 0;
		fread(buff, 1, BUFF, fin);
	}
	return buff[cursor];
}

int getnr(FILE *fin) {
	char ch = getChar(fin);
	while(!isdigit(ch))
		ch = fgetc(fin);
	int nr = 0;
	while(isdigit(ch)) {
		nr = nr * 10 + ch - '0';
		ch = getChar(fin);
	}
	return nr;
}

struct Point {
	int x, y;
} v[MAX_N];

int main() {
	int N, x, y;
	Point pnt;

	N = getnr(stdin);
	int top = 0;
	for(int i = 0; i < N; ++i) {
		x = getnr(stdin);
		y = getnr(stdin);

		pnt = {x - y, x + y};
		
		while(top > 0 && pnt.x <= v[top - 1].x && pnt.y >= v[top - 1].y)
			--top;
		if(top == 0 || (top > 0 && !(v[top - 1].x <= pnt.x && v[top - 1].y >= pnt.y)))
			v[top++] = pnt;
	}

	printf("%d", top);

	return 0;
}

Compilation message (stderr)

lightningrod.cpp: In function 'char getChar(FILE*)':
lightningrod.cpp:13:8: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   fread(buff, 1, BUFF, fin);
   ~~~~~^~~~~~~~~~~~~~~~~~~~

• 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