Submission #856477

#	Time	Username	Problem	Language	Result	Execution time	Memory
856477		RiverFlow	Paths (BOI18_paths)	C++14	100 / 100	386 ms	59740 KiB

paths

#include <bits/stdc++.h>

#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maxi(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
    if (a > b) { a = b; return 1; } return 0;
}

const int N = (int)3e5 + 9;
const int mod = (int)1e9 + 7;

void prepare(); void main_code();

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    const bool MULTITEST = 0; prepare();
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); }
}

void prepare() {};

#define MASK(i) (1 << i)
#define BIT(mask, i) (1 & (mask >> i))

int a[N], dp[N][1 << 5];

vector<int> p[6], g[N];

void main_code() {
    int n, m, k; cin >> n >> m >> k;
    for(int i = 1; i <= n; ++i) cin >> a[i], --a[i];
    for(int i = 1; i <= m; ++i) {
        int u, v; cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    memset(dp, 0, sizeof dp);
    FOR(i, 1, n) dp[i][MASK(a[i])] = 1;
    FOR(mask, 0, MASK(k) - 1) {
        p[__builtin_popcount(mask)].push_back(mask);
    }
    FOR(j, 1, k - 1) {
        for(int t : p[j]) {
            FOR(i, 1, n) for(int v : g[i]) if (BIT(t, a[v]) == 0) {
                dp[v][t ^ MASK(a[v])] += dp[i][t];
            }
        }
    }
    long long res = 0;

    FOR(j, 2, k) for(int t : p[j])
        FOR(i, 1, n) res += dp[i][t];

    cout << res;
}


/*     Let the river flows naturally     */

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
paths.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 23 / 23
• Subtask 2: 20 / 20
• Subtask 3: 27 / 27
• Subtask 4: 30 / 30