Submission #30511

#	Time	Username	Problem	Language	Result	Execution time	Memory
30511		zoomswk	Aliens (IOI16_aliens)	C++14	4 / 100	0 ms	4368 KiB

aliens

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

vector<pair<int, int>> p;
int L[100005], R[100005];
long long dp[100005][2];

void run(int l, int r, int opt_l, int opt_r, int lv){
    if(l > r) return;
    int mid = (l+r)>>1;
    int new_opt = -1;
    int now = lv&1, prev = !now;
    for(int x=opt_l; x<=min(opt_r, mid); x++){
        long long cst = dp[x-1][prev]+1LL*(R[mid]-L[x]+1)*(R[mid]-L[x]+1)-(R[x-1]-L[x]+1 > 0 ? 1LL*(R[x-1]-L[x]+1)*(R[x-1]-L[x]+1): 0LL);
        if(cst < dp[mid][now]){
            dp[mid][now] = cst;
            new_opt = x;
        }
    }
    run(l, mid-1, opt_l, new_opt, lv);
    run(mid+1, r, new_opt, opt_r, lv);
    return;
}

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++) p.push_back({min(r[i], c[i]), -max(r[i], c[i])});
    sort(p.begin(), p.end());
    int N=1, tmp_mx=-1;
    for(int i=0; i<n; i++){
        if(-p[i].second > tmp_mx){
            L[N] = p[i].first, R[N] = -p[i].second;
            tmp_mx = -p[i].second;
            N++;
        }
    }
    N--;
    R[0] = -1e9;
    for(int i=1; i<=min(N, k); i++){
        int now = i&1, prev = !now;
        for(int j=1; j<=N; j++) dp[j][now] = 1e18;
        run(1, N, 1, N, i);
    }
    return dp[N][min(N, k)&1];
}

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:40:24: warning: unused variable 'prev' [-Wunused-variable]
         int now = i&1, prev = !now;
                        ^

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