Submission #1115234

#	Time	Username	Problem	Language	Result	Execution time	Memory
1115234		manhlinh1501	Skyscraper (JOI16_skyscraper)	C++17	20 / 100	209 ms	101532 KiB

skyscraper

#include<bits/stdc++.h>
using namespace std;
using i64 = long long;

template<class X, class Y>
bool minimize(X &x, const Y &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

const int MAXN = 105;
const int MAXL = 1e3 + 5;
const int MOD = 1e9 + 7;

int N, K;
int a[MAXN];

void add(int &a, int b) {
    a += b;
    if(a >= MOD) a -= MOD;
}

namespace Subtask1 {
    bool is_subtask() {
        return N <= 8;
    }
    void Solution() {
        if(is_subtask() == false) return;
        int ans = 0;
        vector<int> p(N, 0);
        iota(p.begin(), p.end(), 1);
        do {
            int x = 0;
            for(int i = 1; i < N; i++) x += abs(a[p[i - 1]] - a[p[i]]);
            if(x <= K) ans++;
        } while(next_permutation(p.begin(), p.end()));
        cout << ans;
        exit(0);
    }
}

namespace Subtask2 {
    bool is_subtask() {
        return N <= 14 and K <= 100;
    }
    int dp[(1 << 14) + 5][15][105];

    void Solution() {
        if(is_subtask() == false) return;
        for(int i = 1; i <= N; i++) dp[1 << (i - 1)][i][0] = 1;
        for(int mask = 1; mask < (1 << N); mask++) {
            for(int i = 1; i <= N; i++) {
                if((mask >> (i - 1) & 1)) {
                    for(int j = 1; j <= N; j++) {
                        if(i == j) continue;
                        int x = abs(a[i] - a[j]);
//                        cout << i << " " << j << " " << x << "\n";
                        for(int z = K; z >= x; z--)
                            add(dp[mask][i][z], dp[mask ^ (1 << (i - 1))][j][z - x]);
                    }
                }
            }
        }
        int ans = 0;
        for(int i = 1; i <= N; i++) {
            for(int j = 0; j <= K; j++)
                add(ans, dp[(1 << N) - 1][i][j]);
        }
//        for(int mask = 0; mask < (1 << N); mask++) {
//            for(int i = 1; i <= N; i++) {
//                for(int j = 0; j <= K; j++)
//                    if(dp[mask][i][j])
//                        printf("mask = %d i = %d j = %d dp = %d\n", mask, i, j, dp[mask][i][j]);
//            }
//        }
        cout << ans << "\n";
        exit(0);
    }
}

signed main() {
#define task ""
    if(fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> N >> K;
    for(int i = 1; i <= N; i++) cin >> a[i];
    Subtask1::Solution();
    Subtask2::Solution();
    return (0 ^ 0);
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80