Submission #250712

#	Time	Username	Problem	Language	Result	Execution time	Memory
250712		Sorting	Building Bridges (CEOI17_building)	C++14	0 / 100	93 ms	65400 KiB

building

#include <bits/stdc++.h>

using namespace std;

const int k_N = 1e5 + 3;
const int k_Max = 1e6 + 3;
const long long k_Inf = 1e18;

struct LiChaoTree{
    struct Line{
        
        long long a, b;
        Line(){}
        Line(long long a, long long b): a(a), b(b){}
        long long operator()(long long x){
            return a * x + b;
        }
    };

    Line lines[4 * k_Max];

    LiChaoTree(){
        for(int i = 0; i < 4 * k_Max; ++i)
            lines[i] = {0, k_Inf};
    }   

    //[l, r)
    void update(int idx, int l, int r, Line new_line){
        int mid = (l + r) >> 1;
        bool lb = new_line(l) < lines[idx](l);
        bool mb = new_line(mid) < lines[idx](mid);

        if(mid)
            swap(lines[idx], new_line);
        if(r - l == 1) return;
        if(lb != mb)
            update(2 * idx + 1, l, mid, new_line);
        else
            update(2 * idx + 2, mid, r, new_line);
    }

    long long get(int idx, int l, int r, int x){
        if(x < l || r < x) return k_Inf;
        if(r - l == 1) return lines[idx](x);

        int mid = (l + r) >> 1;
        return min(lines[idx](x), min(get(2 * idx + 1, l, mid, x), get(2 * idx + 2, mid, r, x)));
    }
};

int n;
long long h[k_N], w[k_N];

long long dp[k_N];
LiChaoTree li_chao;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n;
    for(int i = 0; i < n; ++i)
        cin >> h[i];
    for(int i = 0; i < n; ++i)
        cin >> w[i];

    dp[n - 1] = 0;
    li_chao.update(0, 0, k_Max, LiChaoTree::Line(-2 * h[n - 1], h[n - 1] * h[n - 1]));

    long long sum = 0;
    for(int i = n - 2; i >= 0; --i){
        dp[i] = li_chao.get(0, 0, k_Max, h[i]) + h[i] * h[i] + sum;
        sum += w[i];
        li_chao.update(0, 0, k_Max, LiChaoTree::Line(-2 * h[i], h[i] * h[i] + dp[i] - sum));
    }

    //dp[i] = min(sum + h[i] * h[i] - 2 * h[i] * h[j] + h[j] * h[j] + dp[j], dp[i]);

    cout << dp[0] << "\n";
}
/*
6
3 8 7 1 6 6
0 -1 9 1 2 0
*/

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40