Submission #199373

#	Time	Username	Problem	Language	Result	Execution time	Memory
199373		CaroLinda	Skyscraper (JOI16_skyscraper)	C++14	20 / 100	646 ms	212088 KiB

skyscraper

#include <bits/stdc++.h>

const int MOD = 1e9+7 ;
const int MAXL = 110 ;
const int MAXN = 15 ;

using namespace std ;

int n , l ;
int f[MAXN] ;
long long dp[ (1<<14)+100 ][ MAXL ][ MAXN ] ;

bool isOn(int mask, int i) { return ((1<<i)&mask) != 0 ; } 


int main()
{
    
    scanf("%d%d", &n , &l ) ;
    for(int i = 1 ; i <= n ; i++ ) scanf("%d", &f[i]) ;
    
    if( n <= 8 )
    {
        
        sort( f+1, f+1+n ) ;
        
        int ans = 0 , soma = 0 ;
        
        for(int i = 1 ; i < n ; i++ )
                soma += abs( f[i] - f[i+1] ) ;
        if( soma <= l ) ans ++ ;
        while( next_permutation( f+1, f+1+n ) )
        {
            soma = 0;
            
            for(int i = 1 ; i < n ; i++ )
                soma += abs( f[i] - f[i+1] ) ;
            if( soma <= l ) ans ++ ;
        }
        
        printf("%d\n" , ans ) ;
        return 0 ;
        
    } 
    
    long long ans = 0LL ;
    
    for(int i = l ; i >= 0 ; i-- )
        for(int j = 0 ; j < n ; j++ ) dp[ (1<<n)-1 ][i][j] = 1 ;
    
    for(int mask = (1<<n) - 2 ; mask > 0 ; mask--  )
    {
        
        vector<int> off , on ;
        
        for(int i = 0 ; i < n ; i++ )
        {
            if( isOn(mask, i) ) on.push_back(i) ;
            else off.push_back(i) ;
        }
        
        for(int i = 0 ; i <= l ; i++ )
            for(int j : on )
                for(int k : off)
                {
                    if( i < abs( f[j+1] - f[k+1] ) ) continue ;
                    dp[mask][i][j] = (dp[mask][i][j] + dp[ mask|(1<<k) ][ i - abs( f[j+1] - f[k+1] ) ][ k ] ) % MOD ;
                }
            
            
    }
    
    for(int i = 0 ; i < n ; i++ ) ans = ( ans + dp[ (1<<i) ][l][i] ) % MOD ;
    
    printf("%lld\n" , ans ) ;
    
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:19:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n , &l ) ;
     ~~~~~^~~~~~~~~~~~~~~~~~
skyscraper.cpp:20:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1 ; i <= n ; i++ ) scanf("%d", &f[i]) ;
                                    ~~~~~^~~~~~~~~~~~~

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