Submission #617520

#	Time	Username	Problem	Language	Result	Execution time	Memory
617520		Hazem	Aliens (IOI16_aliens)	C++14	60 / 100	2035 ms	6312 KiB

aliens

#include <bits/stdc++.h>
#define F first
#define S second
#define LL long long

using namespace std;

const int N = 2e5+10;
const LL LINF = 1e18;

pair<int,int>p[N];
LL dp[N],dp1[N];
vector<pair<int,int>>vec;

bool cmp(pair<int,int>p1,pair<int,int>p2){

    if(p1.F!=p2.F)
        return p1.F<p2.F;
    return p1.S>p2.S;
}

LL C(LL a,LL b){

    LL d = (vec[b].F-vec[a].S+1),d1 = max(0,vec[a-1].F-vec[a].S+1);
    d *= d;
    d1 *= d1;
    return d-d1;
}

void compute(int l, int r, int optl, int optr) {
   
    if (l > r)
        return;

    int mid = (l + r) >> 1;
    pair<long long, int> best = {LLONG_MAX, -1};

    for (int k = optl; k <= min(mid, optr); k++) {
        best = min(best, {(k ? dp[k - 1] : 0) + C(k,mid), k});
    }

    dp1[mid] = best.first;
    int opt = best.second;

    compute(l, mid - 1, optl, opt);
    compute(mid + 1, r, opt, optr);
}

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(r[i]>c[i])
            swap(r[i],c[i]);
        p[i] = {c[i],r[i]};
    }    

    sort(p,p+n);
    int mn = 1e9+10;
    for(int i=n-1;i>=0;i--){
        if(mn<=p[i].S)
            continue;
        vec.push_back(p[i]);
        mn = min(mn,p[i].S);
    }

    vec.push_back({-1,-1});
    reverse(vec.begin(),vec.end());

    n = vec.size()-1;

    for(int i=1;i<=n;i++)
        dp[i] = C(1,i);
    
    LL ans = dp[n];
    for(int i=2;i<=k;i++){
        dp[0] = LINF;
        compute(1, n, 1, n);
        for(int j=1;j<=n;j++)
            dp[j] = dp1[j];
        
        ans = min(ans,dp[n]);
    }

    return ans;
}

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