oj.uz

Submission #146655

# Submission time Handle Problem Language Result Execution time Memory
146655 2019-08-25T02:01:19 Z jh05013 None (KOI18_footprint) C++17
55 / 100
 1301 ms 111212 KB 
#include <bits/stdc++.h>
#define entire(X) X.begin(),X.end()
#define LAMB [](point const &a, point const &b)->bool
#define LAMBI [&j](int const &a, int const &b)->bool
using namespace std; typedef long long ll;
void OJize(){cin.tie(NULL); ios_base::sync_with_stdio(false);}

struct point{
    ll x, y;
    point(ll x, ll y): x{x}, y{y} {}
};
ostream &operator<<(ostream &os, point const &p){
    return os << p.x << ' ' << p.y;
}

// positive -> ccw; negative -> cw; 0 -> collinear
ll ccw(point a, point b, point c){
    return (b.x-a.x)*(c.y-a.y) - (b.y-a.y)*(c.x-a.x);
}

int dp[2][3003][3003];
int prv[2][3003][3003];
vector<point> pnts;

int main(){OJize();
    int n; cin>>n;
    for(int i=0; i<n; i++){
        ll x, y; cin>>x>>y;
        pnts.push_back(point(x, y));
    }
    sort(entire(pnts), LAMB{return a.y < b.y;});
    sort(pnts.begin()+1, pnts.end(), LAMB{return ccw(pnts[0], a, b) > 0;});

    // base case
    for(int i=1; i<n; i++) dp[0][0][i] = 2; // 0 = heel
    // update
    for(int j=1; j<n-1; j++){
        vector<int> bef, aft;
        for(int i=0; i<j; i++) bef.push_back(i);
        for(int k=j+1; k<n; k++) aft.push_back(k);
        sort(entire(bef), LAMBI{return ccw(pnts[j], pnts[a], pnts[b]) > 0;});
        sort(entire(aft), LAMBI{return ccw(pnts[j], pnts[a], pnts[b]) > 0;});
        int ptr = 0, maxd = 0, pid = 0;
        for(int k: aft){
            while(ptr<bef.size() && ccw(pnts[j], pnts[k], pnts[bef[ptr]]) > 0){
                int i = bef[ptr++];
                if(i && ccw(pnts[0], pnts[i], pnts[j]) == 0) continue;
                if(dp[0][i][j] && maxd <= dp[0][i][j])
                    maxd = dp[0][i][j]+1, pid = i;
            }
            dp[1][j][k] = maxd, prv[1][j][k] = pid;
        }
        reverse(entire(bef)), reverse(entire(aft));
        ptr = maxd = pid = 0;
        for(int k: aft){
            while(ptr<bef.size() && ccw(pnts[j], pnts[k], pnts[bef[ptr]]) < 0){
                int i = bef[ptr++];
                if(i && ccw(pnts[0], pnts[i], pnts[j]) == 0) continue;
                if(dp[1][i][j] && maxd <= dp[1][i][j])
                    maxd = dp[1][i][j]+1, pid = i;
            }
            dp[0][j][k] = maxd, prv[0][j][k] = pid;
        }
    }

    // answer
    int ans = 0, ai = 0, aj = 0;
    for(int i=1; i<n; i++) for(int j=i+1; j<n; j++){
        if(ccw(pnts[i], pnts[j], pnts[0]) <= 0) continue;
        if(ans < dp[0][i][j]) ans = dp[0][i][j], ai = i, aj = j;
    }
    if(ans == 0){cout << 0; return 0;}
    vector<int> trace = {aj, ai};
    while(trace.back()){
        int sz = trace.size();
        trace.push_back(prv[sz%2][trace[sz-1]][trace[sz-2]]);
    }
    reverse(entire(trace));

    cout<<trace.size()<<'\n';
    for(int x: trace) cout<<pnts[x]<<'\n';
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:45:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             while(ptr<bef.size() && ccw(pnts[j], pnts[k], pnts[bef[ptr]]) > 0){
                   ~~~^~~~~~~~~~~
footprint.cpp:56:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             while(ptr<bef.size() && ccw(pnts[j], pnts[k], pnts[bef[ptr]]) < 0){
                   ~~~^~~~~~~~~~~

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1062 ms 98408 KB Output is correct
2 Correct 1113 ms 100984 KB Output is correct
3 Correct 1126 ms 99636 KB Output is correct
4 Correct 1114 ms 100984 KB Output is correct
5 Correct 1093 ms 100144 KB Output is correct
6 Correct 1108 ms 101044 KB Output is correct
7 Correct 1097 ms 100472 KB Output is correct
8 Correct 1150 ms 101188 KB Output is correct
9 Correct 1110 ms 101624 KB Output is correct
10 Correct 1104 ms 101128 KB Output is correct
11 Correct 1106 ms 101292 KB Output is correct
12 Correct 1114 ms 101752 KB Output is correct
13 Correct 1188 ms 103004 KB Output is correct
14 Correct 1117 ms 101032 KB Output is correct
15 Correct 1115 ms 99936 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 508 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 508 KB Output is correct
5 Correct 2 ms 508 KB Output is correct
6 Correct 2 ms 500 KB Output is correct
7 Correct 2 ms 504 KB Output is correct
8 Correct 2 ms 504 KB Output is correct
9 Correct 2 ms 504 KB Output is correct
10 Correct 2 ms 504 KB Output is correct
11 Correct 2 ms 504 KB Output is correct
12 Correct 2 ms 504 KB Output is correct
13 Correct 2 ms 508 KB Output is correct
14 Correct 2 ms 504 KB Output is correct
15 Correct 1 ms 508 KB Output is correct
16 Correct 2 ms 504 KB Output is correct
17 Correct 2 ms 504 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 504 KB Output is correct
20 Correct 2 ms 504 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 508 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 508 KB Output is correct
5 Correct 2 ms 508 KB Output is correct
6 Correct 2 ms 500 KB Output is correct
7 Correct 2 ms 504 KB Output is correct
8 Correct 2 ms 504 KB Output is correct
9 Correct 2 ms 504 KB Output is correct
10 Correct 2 ms 504 KB Output is correct
11 Correct 2 ms 504 KB Output is correct
12 Correct 2 ms 504 KB Output is correct
13 Correct 2 ms 508 KB Output is correct
14 Correct 2 ms 504 KB Output is correct
15 Correct 1 ms 508 KB Output is correct
16 Correct 2 ms 504 KB Output is correct
17 Correct 2 ms 504 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 504 KB Output is correct
20 Correct 2 ms 504 KB Output is correct
21 Correct 14 ms 5496 KB Output is correct
22 Correct 15 ms 5496 KB Output is correct
23 Correct 13 ms 5348 KB Output is correct
24 Correct 15 ms 5880 KB Output is correct
25 Correct 15 ms 5880 KB Output is correct
26 Correct 16 ms 6008 KB Output is correct
27 Correct 15 ms 5880 KB Output is correct
28 Correct 15 ms 5880 KB Output is correct
29 Correct 15 ms 5880 KB Output is correct
30 Correct 15 ms 5880 KB Output is correct
31 Correct 15 ms 5880 KB Output is correct
32 Correct 15 ms 5800 KB Output is correct
33 Correct 11 ms 5888 KB Output is correct
34 Correct 10 ms 5880 KB Output is correct
35 Correct 10 ms 5880 KB Output is correct

Subtask #4
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 1062 ms 98408 KB Output is correct
2 Correct 1113 ms 100984 KB Output is correct
3 Correct 1126 ms 99636 KB Output is correct
4 Correct 1114 ms 100984 KB Output is correct
5 Correct 1093 ms 100144 KB Output is correct
6 Correct 1108 ms 101044 KB Output is correct
7 Correct 1097 ms 100472 KB Output is correct
8 Correct 1150 ms 101188 KB Output is correct
9 Correct 1110 ms 101624 KB Output is correct
10 Correct 1104 ms 101128 KB Output is correct
11 Correct 1106 ms 101292 KB Output is correct
12 Correct 1114 ms 101752 KB Output is correct
13 Correct 1188 ms 103004 KB Output is correct
14 Correct 1117 ms 101032 KB Output is correct
15 Correct 1115 ms 99936 KB Output is correct
16 Correct 2 ms 508 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 380 KB Output is correct
19 Correct 2 ms 508 KB Output is correct
20 Correct 2 ms 508 KB Output is correct
21 Correct 2 ms 500 KB Output is correct
22 Correct 2 ms 504 KB Output is correct
23 Correct 2 ms 504 KB Output is correct
24 Correct 2 ms 504 KB Output is correct
25 Correct 2 ms 504 KB Output is correct
26 Correct 2 ms 504 KB Output is correct
27 Correct 2 ms 504 KB Output is correct
28 Correct 2 ms 508 KB Output is correct
29 Correct 2 ms 504 KB Output is correct
30 Correct 1 ms 508 KB Output is correct
31 Correct 2 ms 504 KB Output is correct
32 Correct 2 ms 504 KB Output is correct
33 Correct 2 ms 376 KB Output is correct
34 Correct 2 ms 504 KB Output is correct
35 Correct 2 ms 504 KB Output is correct
36 Correct 14 ms 5496 KB Output is correct
37 Correct 15 ms 5496 KB Output is correct
38 Correct 13 ms 5348 KB Output is correct
39 Correct 15 ms 5880 KB Output is correct
40 Correct 15 ms 5880 KB Output is correct
41 Correct 16 ms 6008 KB Output is correct
42 Correct 15 ms 5880 KB Output is correct
43 Correct 15 ms 5880 KB Output is correct
44 Correct 15 ms 5880 KB Output is correct
45 Correct 15 ms 5880 KB Output is correct
46 Correct 15 ms 5880 KB Output is correct
47 Correct 15 ms 5800 KB Output is correct
48 Correct 11 ms 5888 KB Output is correct
49 Correct 10 ms 5880 KB Output is correct
50 Correct 10 ms 5880 KB Output is correct
51 Correct 1092 ms 100760 KB Output is correct
52 Correct 1109 ms 101116 KB Output is correct
53 Correct 1131 ms 102776 KB Output is correct
54 Correct 1286 ms 110840 KB Output is correct
55 Correct 1284 ms 111212 KB Output is correct
56 Correct 1301 ms 110984 KB Output is correct
57 Correct 1295 ms 111072 KB Output is correct
58 Incorrect 1299 ms 110868 KB Output isn't correct
59 Halted 0 ms 0 KB -