Submission #322308

# Submission time Handle Problem Language Result Execution time Memory
322308 2020-11-14T12:36:04 Z lohacho None (KOI18_footprint) C++14
100 / 100
115 ms 748 KB
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long LL;
 
LL ccw(LL a, LL b, LL c, LL d){
    LL rv = a * d - b * c;
    return rv ? rv > 0 ? 1 : -1 : 0;
}
 
LL N;
struct data{
    LL x, y, mx, my;
    bool operator<(const data&r)const{
        return ccw(mx, my, r.mx, r.my) == 1;
    }
}arr[3004];
LL d[3004][3], from[3004][3];
 
void out(LL A, LL B, LL dep){
    if(A == 1){
        printf("%lld\n%lld %lld\n", dep, arr[A].x, arr[A].y);
        return;
    }
    out(from[A][B], 1 - B, dep + 1);
    printf("%lld %lld\n", arr[A].x, arr[A].y);
}
 
int main(){
    scanf("%lld", &N);
    LL low = (LL)1e9, num;
    for(LL i = 1; i <= N; ++i){
        scanf("%lld %lld", &arr[i].x, &arr[i].y);
        if(arr[i].y < low){
            low = arr[i].y, num = i;
        }
    }
    swap(arr[1], arr[num]);
    for(LL i = 1; i <= N; ++i){
        arr[i].mx = arr[i].x - arr[1].x;
        arr[i].my = arr[i].y - arr[1].y;
    }
    sort(arr + 2, arr + N + 1);
    for(LL i = 2; i <= N; ++i){
        d[i][1] = from[i][1] = 1;
    }
    for(LL i = 3; i <= N; ++i){
        for(LL k = 0; k < 2; ++k){
            for(LL j = 2; j < i; ++j){
                if(ccw(arr[i].mx, arr[i].my, arr[j].mx, arr[j].my) == 0){
                    continue;
                }
                if(from[j][1 - k] && ccw(arr[i].x - arr[from[j][1 - k]].x, arr[i].y - arr[from[j][1 - k]].y,
                                         arr[j].x - arr[from[j][1 - k]].x, arr[j].y - arr[from[j][1 - k]].y) == k - (k == 0)){
                    if(d[j][1 - k] + 1 > d[i][k] || !from[i][k] || (d[j][1 - k] + 1 == d[i][k] &&
                        ccw(arr[from[i][k]].x - arr[i].x, arr[from[i][k]].y - arr[i].y,
                            arr[j].x - arr[i].x, arr[j].y - arr[i].y) != k - (k == 0))){
                        d[i][k] = d[j][1 - k] + 1;
                        from[i][k] = j;
                    }
                }
            }
        }
    }
    LL pos, big = -1;
    for(LL i = 2; i <= N; ++i){
        if(d[i][1] > big){
            big = d[i][1], pos = i;
        }
    }
    if(big < 3){
        puts("0"); return 0;
    }
    out(pos, 1, 1);
    return 0;
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:31:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   31 |     scanf("%lld", &N);
      |     ~~~~~^~~~~~~~~~~~
footprint.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   34 |         scanf("%lld %lld", &arr[i].x, &arr[i].y);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
footprint.cpp:32:23: warning: 'num' may be used uninitialized in this function [-Wmaybe-uninitialized]
   32 |     LL low = (LL)1e9, num;
      |                       ^~~
# Verdict Execution time Memory Grader output
1 Correct 71 ms 748 KB Output is correct
2 Correct 73 ms 748 KB Output is correct
3 Correct 72 ms 748 KB Output is correct
4 Correct 75 ms 748 KB Output is correct
5 Correct 74 ms 748 KB Output is correct
6 Correct 75 ms 748 KB Output is correct
7 Correct 74 ms 748 KB Output is correct
8 Correct 82 ms 652 KB Output is correct
9 Correct 74 ms 748 KB Output is correct
10 Correct 73 ms 748 KB Output is correct
11 Correct 74 ms 748 KB Output is correct
12 Correct 74 ms 748 KB Output is correct
13 Correct 78 ms 656 KB Output is correct
14 Correct 75 ms 748 KB Output is correct
15 Correct 74 ms 748 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 236 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 236 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 2 ms 364 KB Output is correct
25 Correct 2 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 2 ms 364 KB Output is correct
28 Correct 2 ms 364 KB Output is correct
29 Correct 2 ms 364 KB Output is correct
30 Correct 2 ms 364 KB Output is correct
31 Correct 2 ms 364 KB Output is correct
32 Correct 2 ms 364 KB Output is correct
33 Correct 1 ms 364 KB Output is correct
34 Correct 2 ms 364 KB Output is correct
35 Correct 1 ms 364 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 71 ms 748 KB Output is correct
2 Correct 73 ms 748 KB Output is correct
3 Correct 72 ms 748 KB Output is correct
4 Correct 75 ms 748 KB Output is correct
5 Correct 74 ms 748 KB Output is correct
6 Correct 75 ms 748 KB Output is correct
7 Correct 74 ms 748 KB Output is correct
8 Correct 82 ms 652 KB Output is correct
9 Correct 74 ms 748 KB Output is correct
10 Correct 73 ms 748 KB Output is correct
11 Correct 74 ms 748 KB Output is correct
12 Correct 74 ms 748 KB Output is correct
13 Correct 78 ms 656 KB Output is correct
14 Correct 75 ms 748 KB Output is correct
15 Correct 74 ms 748 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 236 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 364 KB Output is correct
29 Correct 1 ms 364 KB Output is correct
30 Correct 1 ms 364 KB Output is correct
31 Correct 1 ms 364 KB Output is correct
32 Correct 1 ms 364 KB Output is correct
33 Correct 1 ms 364 KB Output is correct
34 Correct 1 ms 364 KB Output is correct
35 Correct 1 ms 364 KB Output is correct
36 Correct 1 ms 364 KB Output is correct
37 Correct 1 ms 364 KB Output is correct
38 Correct 1 ms 364 KB Output is correct
39 Correct 2 ms 364 KB Output is correct
40 Correct 2 ms 364 KB Output is correct
41 Correct 1 ms 364 KB Output is correct
42 Correct 2 ms 364 KB Output is correct
43 Correct 2 ms 364 KB Output is correct
44 Correct 2 ms 364 KB Output is correct
45 Correct 2 ms 364 KB Output is correct
46 Correct 2 ms 364 KB Output is correct
47 Correct 2 ms 364 KB Output is correct
48 Correct 1 ms 364 KB Output is correct
49 Correct 2 ms 364 KB Output is correct
50 Correct 1 ms 364 KB Output is correct
51 Correct 79 ms 748 KB Output is correct
52 Correct 73 ms 748 KB Output is correct
53 Correct 78 ms 748 KB Output is correct
54 Correct 102 ms 748 KB Output is correct
55 Correct 97 ms 748 KB Output is correct
56 Correct 98 ms 748 KB Output is correct
57 Correct 115 ms 748 KB Output is correct
58 Correct 104 ms 660 KB Output is correct
59 Correct 108 ms 620 KB Output is correct
60 Correct 99 ms 620 KB Output is correct
61 Correct 97 ms 620 KB Output is correct
62 Correct 103 ms 620 KB Output is correct
63 Correct 69 ms 620 KB Output is correct
64 Correct 69 ms 620 KB Output is correct
65 Correct 71 ms 748 KB Output is correct
66 Correct 64 ms 620 KB Output is correct
67 Correct 66 ms 620 KB Output is correct
68 Correct 65 ms 620 KB Output is correct