Submission #546677

#	Time	Username	Problem	Language	Result	Execution time	Memory
546677		lukameladze	Aliens (IOI16_aliens)	C++14	100 / 100	209 ms	7392 KiB

aliens

# include "aliens.h"
# include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define ld long double
#define pii pair <long long, long long> 
using namespace std;
const int N = 1e6 + 5;
long long n,m,k,sk,mx,r[N],c[N],mn,raod,b;
long long ans;
pii dp[N];
struct pi {
    long long l, r;
};
pi a[N];
struct line {
	long long k,b,raod;
};
deque <line> dq;
bool cmp(pi a, pi b) {
    if (a.l != b.l) return (a.l < b.l);
    else
    return (b.r > a.r);
}
long long go(long long le, long long ri) {
    if (le > ri) return 0;
    return (ri - le + 1LL)*(ri - le + 1LL);
}
ld X(line a, line b) {
	//x*(k - k1) = b1 - b
	if (a.k - b.k == 0) assert(false);
	return (ld)((ld)(b.b - a.b)/(ld)(a.k - b.k));
}
long long getans(long long x) {
	while (dq.size() >= 2) {
		line cur = dq[0];
		line prev = dq[1];
		if (X(cur,prev) < (ld)x) 
		dq.pop_front(); 
		else {
			if (X(cur,prev) == (ld)x && cur.raod >= prev.raod) dq.pop_front();
			else break;
		} 
	}
	raod = dq.front().raod + 1LL;
	sk = dq.front().k;
	b = dq.front().b;
	return sk*x + b;
}
void add(long long k, long long b, long long raod) {
     //cout<<k<<"      "<<b<<" "<<raod<<endl;
     if(!dq.size()) {
         dq.push_back({k,b,raod}); return ;
     }
     if (dq.back().k == k) {
         if (dq.back().b > b) dq.pop_back();
         else {
             if (dq.back().raod <= raod) return;
             else dq.pop_back();
         }
     }
     line toadd = {k,b,raod};
     while (dq.size() >= 2) {
         line cur = dq.back();
         line prev = dq[dq.size() - 2];
         if (X(cur,prev) > X(prev,toadd)) {
             dq.pop_back();
         }
         else break;
     }
	dq.push_back(toadd);
}
long long check(long long mid) {
    while (dq.size()) dq.pop_back();
    dp[0] = {0,0};
    long long sk,b;
    raod = 0;
    sk = -2*(a[1].l - 1);  
    b = 0 + (a[1].l - 1)*(a[1].l - 1) - max(0LL, go(a[1].l, a[0].r));
    //cout<<b<<endl;
    add(sk,b,raod);
    //add(-2*a[1].l, 0 + a[1].l*a[1].l - max(0, go(a[1].l, a[0].r)),0);
    for (long long i = 1; i <= n; i++) { 
        
        dp[i] = {1e17,1e17};
        //cout<<"idx -- >"<<i<<" ";
        dp[i].f = getans(a[i].r) + a[i].r*a[i].r + mid;
        dp[i].s = raod;
       //cout<<i<<" "<<dp[i].f<<" "<<dp[i].s<<endl;
       // if (i == 3) cout<<-2*(a[i + 1].l - 1)<<"  "<<dp[i].f - max(0LL,go(a[i + 1].l,a[i].r)) + (a[i + 1].l - 1) * (a[i + 1].l - 1)<<endl;
       if (i != n)
        add(-2*(a[i + 1].l - 1), dp[i].f - max(0LL,go(a[i + 1].l,a[i].r)) + (a[i + 1].l - 1) * (a[i + 1].l - 1), raod);
    }
    //cout<<dp[n].s<<" "<<k<<endl;
    return (dp[n].s <= k);
}
long long take_photos(int nn, int mmm, int kk, vector < int > r, vector < int > c) {
    n = nn;
    m = mmm;
    k = kk;
    for (int i = 0; i < n; i++) {
        r[i]++; c[i]++;
        mn = min(r[i], c[i]); mx = max(r[i],c[i]);
        a[i + 1].l = mn; a[i + 1].r = mx;
    }
    
    sort(a + 1, a + n + 1, cmp);
    long long mm = 0;
    mx = 0;
    for (int i = 1; i <= n; i++) {
        if (mx >= a[i].r) { }
        else {
            mm++; a[mm].l = a[i].l; a[mm].r = a[i].r;
        }
        mx = max(mx,(long long)a[i].r);
    }
    
    long long le, ri,ans1 = 1e15,ans;
    n = mm;
    le = 0;
    ri = m*m;
    while (le <= ri) {
        long long mid = (le + ri) / 2;
        if (check(mid)) {
        	//cout<<mid<<endl;
            ans1 = dp[n].f - k * mid;
            ans = mid; ri = mid - 1; 
        } else { le = mid + 1; }
    }
   // cout<<ans<<endl;
    return ans1;
}
/*
 main() {
    int n, m, k;
    assert(3 == scanf("%d %d %d", &n, &m, &k));
    std::vector<int> r(n), c(n);
    for (int i = 0; i < n; i++) {
        assert(2 == scanf("%d %d", &r[i], &c[i]));
    }
    long long ans = take_photos(n, m, k, r, c);
    
    
    printf("%lld\n", ans);
    return 0;
}*/

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:119:34: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
  119 |     long long le, ri,ans1 = 1e15,ans;
      |                                  ^~~

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