Submission #1041085

#	Time	Username	Problem	Language	Result	Execution time	Memory
1041085		vjudge1	Aliens (IOI16_aliens)	C++17	0 / 100	1 ms	348 KiB

aliens

#include "aliens.h"

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

using lint=int64_t;
using pii=pair<lint,lint>;

#define pb push_back


long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {
    for(int i=0;i<n;i++){
        if(c[i]<r[i]){
            swap(c[i],r[i]);
        }
    }
    int points[m+1];
    memset(points,-1,sizeof(points));
    for(int i=0;i<n;i++){
        points[r[i]]=max(points[r[i]],c[i]);
    }
    vector<pii>pts;
    for(int i=0;i<=m;i++){
        if(points[i]!=-1){
            if(!pts.size()||pts.back().second<points[i]){
                pts.pb(pii{i,points[i]});
            }
        }
    }
    n=pts.size();
    lint a[n],b[n],x[n],ans[n][k+1];
    ans[0][1]=(pts[0].second-pts[0].first+1)*(pts[0].second-pts[0].first+1);
    a[0]=-2*pts[0].first;
    b[0]=-ans[0][1];
    x[0]=pts[0].first*pts[0].first-2*pts[0].first;
    for(int i=1;i<n;i++){
        a[i]=-2*pts[i].first;
        b[i]=-(pts[i].second-pts[i].first+1)*(pts[i].second-pts[i].first+1);
        x[i]=pts[i].first*pts[i].first-2*pts[i].first;
        lint y=(pts[i].second*pts[i].second)+2*pts[i].second+1;
        ans[i][1]=(pts[i].second-pts[0].first+1)*(pts[i].second-pts[0].first+1);
        for(int j=2;j<=min(i+1,k);j++){
            ans[i][j]=ans[i-1][j-1]+(pts[i].second-pts[i].first+1)*(pts[i].second-pts[i].first+1);
            if(pts[i].first<=pts[i-1].second){
                assert(0);
                ans[i][j]-=(pts[i-1].second-pts[i].first+1)*(pts[i-1].second-pts[i].first+1);
            }
            //cerr<<"non "<<i<<" "<<j<<" "<<ans[i][j]<<"\n";
            for(int past=j-1;past<i;past++){
                lint k=(pts[i].second-pts[past].first+1);
                k*=k;
                k+=b[past]+ans[past][j];
                ans[i][j]=min(ans[i][j],k);
                //ans[i][j]=min(ans[i][j],b[past]+x[past]+y+ans[past][j]+a[past]*pts[i].second);
                //cerr<<"for "<<i<<" "<<j<<" extend "<<past<<" :: "<<b[past]+x[past]+y+ans[past][j-1]+a[past]*pts[i].second<<"\n";
                //cerr<<"->> "<<b[past]<<" "<<x[past]<<" "<<y<<" "<<ans[past][j]<<" "<<a[past]*pts[i].second<<"\n";
            }
        }
        /*
        for(int j=1;j<=k;j++){
            cerr<<ans[i][j]<<" ";
        }
        cerr<<"\n";
        */
    }
    //cerr<<b[0]<<"\n";
    //cerr<<n<<"\n";
    lint anss=LLONG_MAX;
    for(int i=1;i<=min(k,n);i++){
        anss=min(anss,ans[n-1][i]);
    }
    return anss;
}

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:41:14: warning: unused variable 'y' [-Wunused-variable]
   41 |         lint y=(pts[i].second*pts[i].second)+2*pts[i].second+1;
      |              ^
aliens.cpp:32:10: warning: variable 'a' set but not used [-Wunused-but-set-variable]
   32 |     lint a[n],b[n],x[n],ans[n][k+1];
      |          ^
aliens.cpp:32:20: warning: variable 'x' set but not used [-Wunused-but-set-variable]
   32 |     lint a[n],b[n],x[n],ans[n][k+1];
      |                    ^

• Subtask 1: 0 / 4
• Subtask 2: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40