Submission #32045

#	Time	Username	Problem	Language	Result	Execution time	Memory
32045		osmanorhan	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	143 ms	45292 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define all( x ) x.begin(), x.end()
#define umin( x, y ) x = min( x, (y) )
#define umax( x, y ) x = max( x, (y) )
#define pb push_back

using namespace std;

typedef long long Lint;
typedef pair<int,int> ii;

const int inf = 1e9 + 137;
const int maxn = 200020;

int a, n;
ii segment[maxn*3];
vector<ii> inc, de;
vector<int> s, ti;

ii find( int l, int r ) {
    ii t = ii( inf, n+1 );
    for(l+=n, r+=n;l<=r;l=(l+1)>>1, r=(r-1)>>1) {
        if( l&1 ) umin( t, segment[l] );
        if( ~r&1 ) umin( t, segment[r] );
    }
    return t;
}

Lint dn[1<<17][20];
int used[1<<17][20];

Lint f( int n, int last ) {
    if( n == (1<<a)-1 ) return 0;
    if( used[n][last] ) return dn[n][last];
    used[n][last] = 1;
    Lint now = ti[last];
    Lint ret = 1e18;
    for(int i=0;i<a;i++)
        if( !((1<<i)&n) ) {
            umin( ret, f( n|(1<<i), i ) + max( 0ll, now-s[i] ) );
        }
    return dn[n][last] = ret;
}

Lint plan_roller_coaster(vector<int> S, vector<int> Ti) {
    s = S;
    ti = Ti;
    a = s.size();

    if( s.size() < 17 ) {
        ti.pb( 1 );
        return f( 0, a );
    }
    for(int i=0;i<a;i++) {
        if( s[i] > ti[i] ) de.pb( ii( ti[i], s[i] ) );
        else inc.pb( ii( s[i], ti[i] ) );
    }
    sort( all( inc ) );
    sort( all( de ) );


    n = 1;
    while( n < inc.size() ) n <<= 1;

    for(int i=1;i<n+n;i++)
        segment[i] = ii( inf, n+1 );

    for(int i=0;i<inc.size();i++)
        segment[i+n] = ii( inc[i].se, i );

    for(int i=n-1;i>=1;i--)
        segment[i] = min( segment[i+i], segment[i+i+1] );

    for(int i=0,now=1;i<de.size();i++) {
        int last = de[i].se;
        //printf("asd--  %d %d\n",last,inc.size());
        bool flag = 1;
        int go = now;
        while( flag ) {
            ii t = find( lower_bound( all( inc ), ii( go, 0 ) ) - inc.begin(), n-1 );
                //printf("--- %d %d -- %d %d\n",t.fi,last,go,n-1);
            if( t.fi <= last ) {
                segment[t.se+n] = ii( inf, n+1 );
                for(int k=(t.se+n)>>1;k;k>>=1)
                    segment[k] = min( segment[k+k], segment[k+k+1] );
                go = t.fi;
            } else break;
        }
        now = de[i].fi;
    }
    ii t = find( 0, n-1 );
    if( t.fi >= inf ) return 0;
    return 1;
}

Compilation message (stderr)

railroad.cpp: In function 'Lint plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:66:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while( n < inc.size() ) n <<= 1;
              ^
railroad.cpp:71:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<inc.size();i++)
                  ^
railroad.cpp:77:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0,now=1;i<de.size();i++) {
                        ^

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36