Submission #109711

#	Time	Username	Problem	Language	Result	Execution time	Memory
109711		popovicirobert	Skyscraper (JOI16_skyscraper)	C++14	0 / 100	3 ms	640 KiB

skyscraper

#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44

using namespace std;

const int MOD = (int) 1e9 + 7;

inline void mod(int &x) {
    if(x >= MOD) x -= MOD;
}

inline void add(int &x, int y) {
    x += y;
    mod(x);
}

const int MAXN = 100;
const int MAXL = 1000;

int dp[2][MAXN + 1][2 * MAXN * (MAXL + 5)][4];

int main() {
    //ifstream cin("A.in");
    //ofstream cout("A.out");
    int i, n, l, j;
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    cin >> n >> l;

    vector <int> arr(n + 1);
    for(i = 1; i <= n; i++) {
        cin >> arr[i];
    }

    sort(arr.begin(), arr.end());

    int sum = 0;
    dp[0][0][2 * MAXN * MAXL][0] = 1;

    for(i = 0; i < n; i++) {
        sum += arr[i];

        for(j = 0; j <= i; j++) {
            int lim = min(sum, l);
            for(int cst = -sum; cst <= lim; cst++) {
                for(int p = 0; p <= 3; p++) {
                    dp[1 - i & 1][j][cst + 2 * MAXL * MAXN][p] = 0;
                }
            }
        }

        for(j = 0; j <= i; j++) {
            int lim = min(sum, l);
            for(int cst = -2 * sum + 2 * MAXN * MAXL; cst <= lim + 2 * MAXN * MAXL; cst++) {

                for(int p = 0; p <= 3; p++) {
                    int cur = dp[i & 1][j][cst][p];
                    if(cur == 0) {
                        continue;
                    }

                    if(cst - 2 * arr[i + 1] >= 0) {
                        add(dp[1 - i & 1][j + 1][cst - 2 * arr[i + 1]][p], cur);
                    }

                    if(cst - arr[i + 1] >= 0) {
                        for(int bit = 0; bit <= 1; bit++) {
                            if((p & (1 << bit)) == 0) {
                                add(dp[1 - i & 1][j + 1][cst - arr[i + 1]][p ^ (1 << bit)], cur);
                            }
                        }
                    }
                }

                for(int p = 0; p <= 3; p++) {
                    int cur = dp[i & 1][j][cst][p];
                    if(cur == 0) {
                        continue;
                    }
                    int num = __builtin_popcount(p);

                    add(dp[1 - i & 1][j][cst][p], (1LL * cur * max(0, 2 * j - num)) % MOD);

                    if(cst + arr[i + 1] <= 2 * MAXN * MAXL + l) {
                        for(int bit = 0; bit <= 1; bit++) {
                            if((p & (1 << bit)) == 0) {
                                if(i < n - 1) {
                                    add(dp[1 - i & 1][j][cst + arr[i + 1]][p ^ (1 << bit)], (1LL * cur * max(0, j - num)) % MOD);
                                }
                                else {
                                    add(dp[1 - i & 1][j][cst + arr[i + 1]][p ^ (1 << bit)], (1LL * cur * j) % MOD);
                                }
                            }
                        }
                    }
                }

                if(j <= 1) {
                    continue;
                }

                for(int p = 0; p <= 3; p++) {
                    int cur = dp[i & 1][j][cst][p];
                    if(cur == 0) {
                        continue;
                    }
                    int a = ((p & 2) > 0), b = (p & 1);

                    if(cst + 2 * arr[i + 1] <= 2 * MAXN * MAXL + l) {
                        if(i < n - 1) {
                            int coef = max(0, a * (j - a - b)) + max(0, (j - a - b) * b) + max(0, (j - a - b) * (j - a - b - 1));
                            add(dp[1 - i & 1][j - 1][cst + 2 * arr[i + 1]][p], (1LL * cur * coef) % MOD);
                        }
                        else {
                            int coef = max(0, a * (j - a - b)) + max(0, (j - a - b) * b) + max(0, (j - a - b) * (j - a - b - 1)) + a * b;
                            add(dp[1 - i & 1][j - 1][cst + 2 * arr[i + 1]][p], (1LL * cur * coef) % MOD);
                        }
                    }
                }

            }

        }
    }

    int ans = 0;
    for(i = 2 * MAXN * MAXL; i <= l + 2 * MAXN * MAXL; i++) {
        ans += dp[n & 1][1][i][3];
        mod(ans);
    }

    cout << ans;

    //cin.close();
    //cout.close();
    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:52:26: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                     dp[1 - i & 1][j][cst + 2 * MAXL * MAXN][p] = 0;
                        ~~^~~
skyscraper.cpp:68:34: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                         add(dp[1 - i & 1][j + 1][cst - 2 * arr[i + 1]][p], cur);
                                ~~^~~
skyscraper.cpp:74:42: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                                 add(dp[1 - i & 1][j + 1][cst - arr[i + 1]][p ^ (1 << bit)], cur);
                                        ~~^~~
skyscraper.cpp:87:30: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                     add(dp[1 - i & 1][j][cst][p], (1LL * cur * max(0, 2 * j - num)) % MOD);
                            ~~^~~
skyscraper.cpp:93:46: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                                     add(dp[1 - i & 1][j][cst + arr[i + 1]][p ^ (1 << bit)], (1LL * cur * max(0, j - num)) % MOD);
                                            ~~^~~
skyscraper.cpp:96:46: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                                     add(dp[1 - i & 1][j][cst + arr[i + 1]][p ^ (1 << bit)], (1LL * cur * j) % MOD);
                                            ~~^~~
skyscraper.cpp:117:38: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                             add(dp[1 - i & 1][j - 1][cst + 2 * arr[i + 1]][p], (1LL * cur * coef) % MOD);
                                    ~~^~~
skyscraper.cpp:121:38: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
                             add(dp[1 - i & 1][j - 1][cst + 2 * arr[i + 1]][p], (1LL * cur * coef) % MOD);
                                    ~~^~~

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