Submission #463381

#	Time	Username	Problem	Language	Result	Execution time	Memory
463381		LptN21	Uzastopni (COCI15_uzastopni)	C++14	160 / 160	110 ms	23688 KiB

uzastopni

#include <bits/stdc++.h>
using namespace std;
#define fastIO ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
#define FF first
#define SS second
#define pb push_back
#define sz(x) (int)x.size()
#define PI acos(-1.0)
#define lb lower_bound
#define ub upper_bound
#define all(a) (a).begin(), (a).end()
#define odd(x) __builtin_parity((int)x)
#define cntbit(x) __builtin_popcount(x)
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<ii, int> i3;
const int N = 1e4+7, M=1e2+1;
const int MOD = 1e9+7;
const int oo = 1e15+7;

int n, m, k, t;

int a[N];
vector<int> adj[N], q[M];
vector<ii> segment[N];
bitset<M> mark[N][M];

void dfs(int u, int p=-1) {
    for(int v:adj[u]) if(v!=p) dfs(v, u);
    for(int i=1;i<M;i++) q[i].clear();
    for(int v:adj[u]) if(v!=p)
        for(ii s:segment[v]) q[s.FF].pb(s.SS);
    for(int l=M-1;l>0;l--) {
        if(l==a[u]) {
            mark[u][l]|=mark[u][l+1];
            mark[u][l].set(l);
        } else {
            for(int r:q[l]) if(r<a[u]||l>a[u]) {
                mark[u][l]|=mark[u][r+1];
                mark[u][l].set(r);
            }
        }
        for(int r=M-1;r>=l;r--)
            if(mark[u][l].test(r)&&r>=a[u]&&l<=a[u])
                segment[u].pb(ii(l, r));
    }
}

signed main() {
    //freopen("test.inp", "r", stdin);
    //freopen("test.out", "w", stdout);
    //fastIO;
    scanf("%d", &n);
    int u, v;
    for(int i=1;i<=n;i++) scanf("%d", &a[i]);
    for(int i=1;i<n;i++) {
        scanf("%d%d", &u, &v);
        adj[u].pb(v), adj[v].pb(u);
    }
    dfs(1);
    printf("%d", sz(segment[1]));
    return 0;
}
/* stuff you should look for
    - int overflow, array bounds
    - special cases (n=1?)
    - do smth instead of do nothing and stay organized
    - WRITE STUFF DOWN
    - DONT JUST STICK ON ONE APPROACH
*/

Compilation message (stderr)

uzastopni.cpp:19:20: warning: overflow in conversion from 'double' to 'int' changes value from '1.000000000000007e+15' to '2147483647' [-Woverflow]
   19 | const int oo = 1e15+7;
      |                ~~~~^~
uzastopni.cpp: In function 'int main()':
uzastopni.cpp:53:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
uzastopni.cpp:55:32: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |     for(int i=1;i<=n;i++) scanf("%d", &a[i]);
      |                           ~~~~~^~~~~~~~~~~~~
uzastopni.cpp:57:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         scanf("%d%d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 160 / 160