Submission #209544

#	Time	Username	Problem	Language	Result	Execution time	Memory
209544		Alexa2001	Lightning Rod (NOI18_lightningrod)	C++17	100 / 100	794 ms	224076 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int Nmax = 1e7 + 5;

int x[Nmax], y[Nmax], n;
bitset<Nmax> good;

const int bsize = 1<<18;
char buffer[bsize+2];
int cursor;

static inline void init_read()
{
    fread(buffer, 1, bsize, stdin), cursor = 0;
}

void read(int &x)
{
    x = 0;
    while(!isdigit(buffer[cursor]))
    {
        ++cursor;
        if(cursor == bsize) init_read();
    }
    while(isdigit(buffer[cursor]))
    {
        x = x * 10 + buffer[cursor] - '0';
        ++cursor;
        if(cursor == bsize) init_read();
    }   
}

int main()
{
   // freopen("input", "r", stdin);
    
    init_read();

    int i;
    int ans = 0;
    read(n);

    for(i=1; i<=n; ++i) read(x[i]), read(y[i]);

    int mx = INT_MIN;
    for(i=1; i<=n; ++i)
        if(x[i] + y[i] > mx) good[i] = 1, mx = x[i] + y[i];
    
    mx = INT_MIN;
    for(i=n; i; --i)
        if(y[i] - x[i] > mx) mx = y[i] - x[i], ans += good[i];

    cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

lightningrod.cpp: In function 'void init_read()':
lightningrod.cpp:16:35: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     fread(buffer, 1, bsize, stdin), cursor = 0;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~

• 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