Submission #497874

#	Time	Username	Problem	Language	Result	Execution time	Memory
497874		kevin	Wiring (IOI17_wiring)	C++17	100 / 100	51 ms	11660 KiB

wiring

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

#define ll long long
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define ca(v) for(auto i:v) cout<<i<<" ";
#define nl cout<<"\n"

const int MAXN = 5e5 + 5;

ll min_total_length(vector<int> a, vector<int> b){
    vector<pair<ll, int>> ar;
    for(int i:a) ar.push_back({(ll)i, 0});
    for(int i:b) ar.push_back({(ll)i, 1});
    sort(ar.begin(), ar.end());
    int p = 0;
    int pv = -1;
    vector<ll> val[2];
    // 0 = <, 1 = >, so add
    // 0 is pref, 1 is posts
    while(p < (int)ar.size()){
        vector<ll> v;
        ll x = ar[p].f;
        v.push_back(x);
        while(p < (int)ar.size() - 1 && ar[p].s == ar[p+1].s) v.push_back(ar[++p].f);
        // ca(v); nl;
        p++;
        // cout<<p<<" ";
        ll iv = (p == (int)ar.size()?0:ar[p].f-ar[p-1].f);
        if(pv == -1){
            if(p == (int)ar.size()) return 0;
            val[0] = val[1] = vector<ll>(v.size() + 1, 1e18);
            ll sm = 0;
            for(ll i:v) sm += v.back() - i;
            val[0][v.size()] = val[1][v.size()] = sm;
        }
        else{
            // cout<<x<<" "<<pv<<"\n";
            vector<ll> nxt[2]; nxt[0] = nxt[1] = vector<ll>(v.size() + 1);
            ll lsm = 0;
            ll rsm = 0;
            for(int i=0; i<(int)v.size(); i++) rsm += v.back() - v[i];
            // cout<<lsm<<" "<<rsm<<"\n";
            nxt[0][v.size()] = val[0][0] + rsm;
            for(int i=1; i<=(int)v.size(); i++){
                if(i) {
                    lsm += v[i-1] - v[0];
                    rsm -= v.back() - v[i-1];
                }
                int id = min(i, (int)val[0].size()-1);
                // cout<<"Val: "<<val[0][id]<<" "<<(int)(i) * (x-pv)<<" "<<(i<(int)val[1].size()?val[1][i]:1e18)<<" "<<lsm<<" "<<rsm<<"\n";
                nxt[0][v.size()-i] = min(val[0][id] + (ll)(i) * (x-pv), (ll)(i<(int)val[1].size()?val[1][i]:1e18)) + lsm + rsm;
            }
            // nxt[0][0] = val[0][val[0].size()-1] + lsm;
            val[0] = nxt[0];
            nxt[0].clear(); nxt[1].clear();
        }
        val[1] = val[0];
        pv = ar[p-1].f;      
        for(int i=0; i<val[0].size(); i++) val[1][i] += i * iv;
        // ca(val[0]);  nl; ca(val[1]); nl;  
        for(int i=1; i<(int)val[0].size(); i++){
            val[0][i] = min(val[0][i], val[0][i-1]);
            val[1][val[0].size()-1-i] = min(val[1][val[0].size()-i], val[1][val[0].size()-1-i]);
        }
        // ca(val[0]); nl; ca(val[1]); nl; nl;
        if(p == ar.size()) return val[0][0];
    }
}

Compilation message (stderr)

wiring.cpp: In function 'long long int min_total_length(std::vector<int>, std::vector<int>)':
wiring.cpp:62:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |         for(int i=0; i<val[0].size(); i++) val[1][i] += i * iv;
      |                      ~^~~~~~~~~~~~~~
wiring.cpp:69:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |         if(p == ar.size()) return val[0][0];
      |            ~~^~~~~~~~~~~~
wiring.cpp:14:27: warning: control reaches end of non-void function [-Wreturn-type]
   14 |     vector<pair<ll, int>> ar;
      |                           ^~

• Subtask 1: 7 / 7
• Subtask 2: 13 / 13
• Subtask 3: 10 / 10
• Subtask 4: 25 / 25
• Subtask 5: 45 / 45