Submission #391717

#	Time	Username	Problem	Language	Result	Execution time	Memory
391717		saarang123	K blocks (IZhO14_blocks)	C++17	0 / 100	1 ms	256 KiB

blocks

#include <bits/stdc++.h>
using namespace std;
const int mxn = 100 * 1000 + 3;
int a[mxn], p[mxn], dp[mxn][103], n, k, mx = 0;

signed main() {
    std::ios::sync_with_stdio(0);
    std::cout.tie(0);
    std::cin.tie(0);
    #ifdef saarang
    freopen("/home/saarang/Documents/cp/input.txt", "r", stdin);
    freopen("/home/saarang/Documents/cp/output.txt", "w", stdout);
    #endif
    cin >> n >> k;
    vector<array<int, 2>> l(n + 1), r(n + 1);
    for(int i = 1; i <= n; i++) {
    	cin >> a[i];
    	l[i][0] = r[i][0] = i;
    	l[i][1] = r[i][1] = i;
    	mx = max(mx, a[i]);
    	dp[1][i] = mx;
    }
    stack<int> s;
    for(int i = 1; i <= n; i++) {
    	while(!s.empty() && a[s.top()] <= a[i])
    		s.pop();
    	l[i][0] = s.empty() ? 1 : s.top() + 1;
    	s.push(i);
    }
    while(!s.empty()) s.pop();
    for(int i = n; i; i--) {
    	while(!s.empty() && a[s.top()] <= a[i])
    		s.pop();
    	r[i][0] = s.empty() ? n : s.top() - 1;
    	s.push(i);
    }
    // for(int i = 1; i <= n; i++)
    // 	cout << l[i][0] << ' ' << r[i][0] << '\n';
    sort(l.begin() + 1, l.end());
    sort(r.begin() + 1, r.end());
    for(int i = 2; i <= k; i++) {
    	deque<array<int, 2>> dq;
    	for(int x = 1; x <= n; x++) {
    		auto &[id, j] = l[x];
    		while(!dq.empty() && dq.back()[0] >= dp[i - 1][j])
    			dq.pop_back();
    		dq.push_back({dp[i - 1][j], j});
    		while(!dq.empty() && dq.front()[1] < id)
    			dq.pop_front();
    		dp[i][j] = dq.empty() ? 1e9 : (a[j] + dq.front()[0]);
    	}
    }
    // for(int i = 1; i <= k; i++) {
    // 	for(int j = 1; j <= n; j++)
    // 		cout << dp[i][j] << ' ';
    // 	cout << '\n';
    // }
    cout << dp[k][n] << '\n';
    return 0;
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 18
• Subtask 3: 0 / 21
• Subtask 4: 0 / 47