Submission #585577

#TimeUsernameProblemLanguageResultExecution timeMemory
585577kawaiiSplit the sequence (APIO14_sequence)C++14
78 / 100
675 ms87704 KiB
#include <bits/stdc++.h> using namespace std; #define fi first #define se second long long t, n, m, k, a[100005], dp[100005], sum[100005], mod = 1e9 + 7, inf = 1e18; int trace[100005][205]; string s; mt19937_64 rng; struct lines{ long long a, b, index; lines(long long a = 0, long long b = 0, long long index = 0) : a(a), b(b), index(index){} long long f(long long x){ return 1LL * a * x + b; }; }; long double slope(lines ln1, lines ln2) { return (long double) (ln2.b - ln1.b) / (long double) (ln2.a - ln1.a); } struct cht{ vector<lines> lns; long long ptr = 0; void add(long long a, long long b, long long index){ lines ln(a, b, index); while(lns.size() > 1 && (slope(lns[lns.size() - 2], lns.back()) - slope(lns[lns.size() - 2], ln)) <= 1e-18) lns.pop_back(); lns.push_back(ln); ptr = min(ptr, (long long) lns.size() - 1); } pair<long long, long long> get(long long x){ if(lns.empty()) return {-inf, 0}; while (ptr + 1 < lns.size() && lns[ptr].f(x) <= lns[ptr + 1].f(x)) ptr++; return {lns[ptr].f(x), lns[ptr].index}; } }; cht osu[5]; void solve(){ osu[0].add(0, 0, 0); for(long long j = 1; j <= k; j++){ for(long long i = 1; i <= n; i++){ long long num = sum[i] * sum[n] - sum[i] * sum[i]; pair<long long, long long> x = osu[0].get(sum[i] - sum[n]); dp[i] = x.fi + num; trace[i][j] = x.se; osu[1].add(sum[i], dp[i], i); // cout << dp[i] <<" "<< i <<" "<< j <<" "<< trace[i][j] << "\n"; } osu[0] = osu[1]; osu[1].lns.clear(); osu[1].ptr = 0; } long long answer = 0; for(long long i = 1; i <= n; i++) answer = max(answer, dp[i]); cout << answer << "\n"; for(long long i = n; i >= 1; i--){ if(answer != dp[i]) continue; vector<long long> v; int x = i; for(long long i = k; i >= 1; i--){ // cout << x <<" "; v.push_back(x); x = max(1, min(trace[x][i], x - 1)); } reverse(v.begin(), v.end()); for(auto i: v) cout << i <<" "; return; } } signed main(){ ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr); rng.seed((long long)main ^ time(0)); #ifdef Kawaii auto starttime = chrono::high_resolution_clock::now(); #endif cin >> n >> k; // n = 1e5, k = 200; for(long long i = 1; i <= n; i++){ cin >> a[i]; // a[i] = rng() % 10001; sum[i] = sum[i - 1] + a[i]; } solve(); #ifdef Kawaii auto endtime = chrono::high_resolution_clock::now(); auto duration = chrono::duration_cast<chrono::milliseconds>(endtime - starttime).count(); cout << "\n=====" << "\nUsed: " << duration << " ms\n"; #endif }

Compilation message (stderr)

sequence.cpp: In member function 'std::pair<long long int, long long int> cht::get(long long int)':
sequence.cpp:33:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<lines>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |         while (ptr + 1 < lns.size() && lns[ptr].f(x) <= lns[ptr + 1].f(x)) ptr++;
      |                ~~~~~~~~^~~~~~~~~~~~
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