Submission #970284

#TimeUsernameProblemLanguageResultExecution timeMemory
970284CSQ31Wiring (IOI17_wiring)C++17
100 / 100
53 ms12484 KiB
#include "wiring.h" #include <bits/stdc++.h> #define sz(a) a.size() using namespace std; typedef long long int ll; const ll INF = 1e16; const int MAXN = 2e5+5; ll pre[MAXN],suff[MAXN]; //pre and suff min ll min_total_length(vector<int> R,vector<int> B) { vector<array<int,2>>a; for(int x:R)a.push_back({x,0}); for(int x:B)a.push_back({x,1}); sort(a.begin(),a.end()); vector<vector<int>>b; int n = sz(a); for(int i=0;i<n;i++){ int j = i; b.push_back({a[i][0]}); while(j+1<n && a[j][1] == a[j+1][1]){ j++; b.back().push_back(a[j][0]); } i = j; } vector<int>s; for(auto x:b)s.push_back(sz(x)); for(int i=0;i<=n;i++)suff[i] = pre[i] = INF; pre[s[0]] = suff[s[0]] = 0; for(int i=0;i<s[0];i++){ pre[s[0]] += b[0].back() - b[0][i]; suff[s[0]] += b[0].back() - b[0][i]; } //compute prefix and suffix min suff[s[0]] += 1LL * s[0] * (b[1][0] - b[0].back()); //distance in between int t = max(s[0],s[1]); for(int i=1;i<=t;i++)pre[i] = min(pre[i],pre[i-1]); for(int i=t-1;i>=0;i--)suff[i] = min(suff[i],suff[i+1]); /* for(auto x:b){ for(int y:x)cout<<y<<" "; cout<<'\n'; }*/ for(int i=1;i<sz(s);i++){ vector<ll>tmp(s[i]+1,0); //tmp[i] = min cost if i guys from this batch is assigned to the left ll cur = 0; for(int j=0;j<=s[i];j++){ if(j)cur += b[i][j-1] - b[i][0]; ll x = pre[j] + 1LL * j * (b[i][0] - b[i-1].back()); //distance in between ll y = suff[j]; tmp[j] = cur + min(x,y); } cur = 0; reverse(tmp.begin(),tmp.end()); for(int j=0;j<=s[i];j++){ if(j)cur += b[i].back() - b[i][s[i]-j]; tmp[j] += cur; } /* cout<<"at "<<i<<'\n'; for(ll x:tmp)cout<<x<<" "; cout<<'\n';*/ //tmp[i] = min cost if i guys assigned to the right if(i == sz(s)-1)return tmp[0]; int t = max(s[i],s[i+1]); for(int j=0;j<=t;j++)pre[j] = suff[j] = INF; for(int j=0;j<=s[i];j++){ pre[j] = suff[j] = tmp[j]; suff[j] += 1LL * j * (b[i+1][0] - b[i].back()); } for(int j=1;j<=t;j++)pre[j] = min(pre[j],pre[j-1]); for(int j=t-1;j>=0;j--)suff[j] = min(suff[j],suff[j+1]); } return 0; }

Compilation message (stderr)

wiring.cpp: In function 'll min_total_length(std::vector<int>, std::vector<int>)':
wiring.cpp:47:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |  for(int i=1;i<sz(s);i++){
      |               ^
wiring.cpp:69:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |   if(i == sz(s)-1)return tmp[0];
      |      ~~^~~~~~~~~~
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