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답안 #1023878

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1023878 2024-07-15T08:26:36 Z caterpillow Burza (COCI16_burza) C++17
0 / 160
 342 ms 508604 KB 
#include <bits/stdc++.h>
#include <random>
 
using namespace std;
 
using ll = long long;
using pl = pair<ll, ll>;
using pi = pair<int, int>;
#define vt vector
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(), x.end() 
#define size(x) ((int) (x).size())
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define F0R(i, b) FOR (i, 0, b)
#define endl '\n'
const ll INF = 1e18;
const int inf = 1e9;
 
template<template<typename> class Container, typename T>
ostream& operator<<(ostream& os, Container<T> o) {
    os << "{"; 
    int g = size(o); 
    for (auto i : o) os << i << ((--g) == 0 ? "" : ", "); 
    os << "}";
    return os;
}
 
void _print() {
    cerr << "\n";
}
 
template<typename T, typename ...V>
void _print(T t, V... v) {
    cerr << t; if (sizeof...(v)) cerr << ", "; _print(v...);
}
 
#ifdef LOCAL
#define dbg(x...) cerr << #x << " = "; _print(x);
#else
#define dbg(x...)
#define cerr if (0) std::cerr
#endif
 
/*
 
you want to stop the coin from taking a path of length k
you only block off nodes at the same depth as the turn number
    ie you block off one of the immediate subtrees
hence, you block off one node at depths 1, 2, 3, ... k
 
take dfs order
 
let dp[i][j][k] be the max # of depth k nodes u can block off 
    considering the flattened array starting from index i
 
    if you take the current node (and its allowed) you split the range and take the sum of the dps in its next sibling (or next node, if non exists)
    otherwise, you go into the next node
 
*/
 
void sus_assert(bool pred) { if (!pred) while (1); }
 
int n, k, t;
vt<vt<int>> adj;
vt<int> depth, pos, jump, val, rpos;
 
vt<int> sfx;
 
void dfs(int u, int p = -1) {
    pos[u] = t++;
    if (depth[u] == k) val[u] = 1;
    for (int v : adj[u]) {
        if (v == p) continue;
        depth[v] = depth[u] + 1;
        dfs(v, u);
        val[u] += val[v];
    }
    jump[u] = t;
}
 
int memo[400][400][400];
 
int dp(int i, int l, int r) {
    if (i == n) return 0;
    if (l > r) return 0;
    if (memo[i][l][r] != -1) return memo[i][l][r];
    int u = rpos[i]; // get the actual node index at this position
 
    int ans = 0;
    if (l <= depth[u] && depth[u] <= r) { // allowed to take yourself
        ans = val[u] + dp(jump[u], l, depth[u] - 1) + dp(jump[u], depth[u] + 1, r);
    }
    ans = max(ans, dp(i + 1, l, r));
    
    assert(ans <= sfx[i]);
 
    return memo[i][l][r] = ans;
}
 
main() {
    cin.tie(0)->sync_with_stdio(0);
    
    cin >> n >> k;
    adj.resize(n);
    depth = pos = jump = val = rpos = vt<int>(n, 0);
    F0R (i, n - 1) {
        int u, v; cin >> u >> v;
        u--, v--;
        adj[u].pb(v);
        adj[v].pb(u);
    }
 
    dfs(0);
    F0R (i, n) rpos[pos[i]] = i;
    memset(memo, -1, sizeof(memo));
 
    sfx.resize(n + 1);
    ROF (i, 0, n) sfx[i] += sfx[i + 1] + (depth[rpos[i]] == k);
    dbg(sfx);
 
    dbg(depth);
    dbg(pos);
    dbg(jump);
    dbg(val);
    dbg(rpos);
 
    // sanity check
    int cnt = 0;
    F0R (i, n) if (depth[i] == k) cnt++;
    sus_assert(val[0] == cnt);
    F0R (i, n) if (depth[i] > k) assert(val[i] == 0);
 
    int ans = dp(0, 1, k);
    dbg(ans);
    assert(ans <= val[0]);
    if (ans == val[0]) cout << "DA\n";
    else cout << "NE\n";
}

Compilation message

burza.cpp:103:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  103 | main() {
      | ^~~~

Subtask #1
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 318 ms 508452 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #2
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 287 ms 508604 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #3
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 342 ms 508496 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #4
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 306 ms 508532 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #5
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 276 ms 508500 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #6
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 300 ms 508356 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #7
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 300 ms 508560 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #8
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 298 ms 508432 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #9
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 289 ms 508460 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #10
0 / 16.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 308 ms 508496 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -