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Submission #146984

# Submission time Handle Problem Language Result Execution time Memory
146984 2019-08-27T02:28:03 Z jun6873 Lightning Rod (NOI18_lightningrod) C++11
0 / 100
 2000 ms 156344 KB 
#include <bits/stdc++.h>
using namespace std;

using lint = long long;
using pint = pair<lint, lint>;
#define x first
#define y second

int n, k;
pint a[10000004], c[10000004];

int ccw(pint a, pint b, pint c) {
    lint k = a.x*b.y + b.x*c.y + c.x*a.y - b.x*a.y - c.x*b.y - a.x*c.y;
    if (k>0) return 1;
    if (k<0) return -1;
    return 0;
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);

    cin >> n;
    for (int i=0; i<n; i++) {
        int x, y;
        cin >> x >> y;
        a[i] = pint(x+y, y-x);
    }

    sort(a, a+n);

    c[k++] = a[0];

    for (int i=1; i<n; i++) {
        while (k>=2 and ccw(c[k-2], c[k-1], a[i]) >= 0) k--;
        c[k++] = a[i];
    }

    int ans = k;
    if (k >= 2 and a[0].y == a[1].y) ans--;
    if (k >= 2 and a[k-2].x == a[k-1].x) ans--;

    cout << ans << '\n';
}

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2069 ms 147792 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Incorrect 2 ms 376 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Incorrect 2 ms 376 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Incorrect 2 ms 376 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Incorrect 2 ms 376 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2053 ms 156344 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2069 ms 147792 KB Time limit exceeded
2 Halted 0 ms 0 KB -