Submission #986433

#	Time	Username	Problem	Language	Result	Execution time	Memory
986433		Zero_OP	Watching (JOI13_watching)	C++14	100 / 100	63 ms	16472 KiB

watching

#include<bits/stdc++.h>

using namespace std;
using int64 = int64_t;

#define  FOR(i, l, r) for(int i = (l), _r = (r); i <= _r; ++i)
#define FORD(i, r, l) for(int i = (r), _l = (l); i >= _l; --i)
#define  rep(i, l, r) for(int i = (l), _r = (r); i < _r; ++i)
#define repd(i, r, l) for(int i = (r) - 1, _l = l; i >= _l; --i)
#define          left __left
#define         right __right
#define          next __next
#define          prev __prev
#define           div __div
#define            pb push_back
#define            pf push_front
#define        all(v) v.begin(), v.end()
#define         sz(v) (int)v.size()
#define    compact(v) v.erase(unique(all(v)), end(v))
#define        dbg(v) "[" #v " = " << (v) << "]"
#define    file(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }

template<typename T>
    bool minimize(T& a, const T& b){
        if(a > b) return a = b, true;
        return false;
    }

template<typename T>
    bool maximize(T& a, const T& b){
        if(a < b) return a = b, true;
        return false;
    }

template<int dimension, typename T>
struct vec : public vector<vec<dimension - 1, T>> {
    static_assert(dimension > 0, "Dimension must be positive !\n");
    template<typename... Args>
    vec(int n = 0, Args... args) : vector<vec<dimension - 1, T>> (n, vec<dimension - 1, T>(args...)) {}
};

template<typename T>
struct vec<1, T> : public vector<T> {
    vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};

void preprocess();
void init();
void process();

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    file("antuvu");
    preprocess();

    int T = 1; //cin >> T;
    while(T--){
        init();
        process();
    }

    return 0;
}

const int MAX = 2e3 + 5;

int n, p, q, a[MAX], reach_w[MAX], reach_2w[MAX], dp[MAX][MAX];

void preprocess(){

}

void init(){
    cin >> n >> p >> q;
    for(int i = 1; i <= n; ++i){
        cin >> a[i];
    }
}

bool f(int w){
    for(int i = 1, j = 1, k = 1; i <= n; ++i){
        while(j < n && a[j + 1] - a[i] + 1 <= w){
            ++j;
        }

        reach_w[i] = j;

        while(k < n && a[k + 1] - a[i] + 1 <= 2 * w){
            ++k;
        }

        reach_2w[i] = k;
    }

    if(reach_w[1] == n || reach_2w[1] == n) return true;

    memset(dp, -1, sizeof(dp));
    dp[0][1] = reach_2w[1];
    dp[1][0] = reach_w[1];

    for(int i = 0; i <= p; ++i){
        for(int j = 0; j <= q; ++j) if(i || j){
            if(dp[i][j] == n){
                return true;
            }

            dp[i + 1][j] = max(dp[i + 1][j], reach_w[dp[i][j] + 1]);
            dp[i][j + 1] = max(dp[i][j + 1], reach_2w[dp[i][j] + 1]);
        }
    }

    return false;
}

void process(){
    if(p + q >= n){
        cout << 1 << '\n';
        return;
    }

    sort(a + 1, a + 1 + n);

    int l = 1, r = 1e9, ans = r;
    while(l <= r){
        int mid = l + r >> 1;
        if(f(mid)) ans = mid, r = mid - 1;
        else l = mid + 1;
    }
    cout << ans << '\n';
}

Compilation message (stderr)

watching.cpp: In function 'void process()':
watching.cpp:127:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  127 |         int mid = l + r >> 1;
      |                   ~~^~~
watching.cpp: In function 'int main()':
watching.cpp:21:58: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 | #define    file(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:55:5: note: in expansion of macro 'file'
   55 |     file("antuvu");
      |     ^~~~
watching.cpp:21:91: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 | #define    file(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:55:5: note: in expansion of macro 'file'
   55 |     file("antuvu");
      |     ^~~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50