# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
43038 | top34051 | Aliens (IOI16_aliens) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "aliens.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll,ll>
#define X first
#define Y second
const int maxn = 1e5 + 5;
struct line {
ll m,c;
line(ll _m = 0, ll _c = 0) {
m = _m; c = _c;
}
};
int n,m,k;
pii p[maxn];
int r[maxn], c[maxn];
ll dp[maxn][maxn];
line cht[maxn];
bool cmp(pii x, pii y) {
if(x.X!=y.X) return x.X<y.X;
return x.Y>y.Y;
}
ll p2(ll x) { return x*x; }
double cut(int x, int y) {
if(x==0 || y==0) return -2e16;
return (double)(cht[y].c-cht[x].c)/(cht[x].m-cht[y].m);
}
void solve() {
for(int x=1;x<=n;x++) dp[x][0] = 1e13;
for(int t=1;t<=k;t++) {
int len = 0;
for(int x=1;x<=n;x++) {
cht[++len] = line(-2*r[x], p2(r[x]) + dp[x-1][t-1] - p2(max(0,c[x-1]-r[x])));
while(len>=3 && cut(len-1,len)<=cut(len-2,len)) cht[len-1] = cht[len], len--;
int l = 2, r = len, mid, pos = 1;
while(l<=r) {
int mid = (l+r)/2;
if(cut(mid-1,mid)<=c[x]) pos = mid, l = mid+1;
else r = mid-1;
}
dp[x][t] = cht[pos].m*c[x] + cht[pos].c + p2(c[x]);
// printf("dp %d %d = %lld\n",x,t,dp[x][t]);
}
}
}
long long take_photos(int N, int M, int K, std::vector<int> R, std::vector<int> C) {
n = N; m = M; k = K;
//prep
for(int i=0;i<n;i++) {
p[i] = {R[i],C[i]};
if(p[i].X>p[i].Y) swap(p[i].X,p[i].Y);
}
sort(p,p+n,cmp);
ll cur = -1, sz = 0;
for(int i=0;i<n;i++) {
if(p[i].Y<=cur) continue;
sz++;
r[sz] = p[i].X; c[sz] = p[i].Y+1;
cur = p[i].Y;
}
n = sz;
solve();
return dp[n][k];
}