Submission #1349959

#TimeUsernameProblemLanguageResultExecution timeMemory
1349959tamir1Bigger segments (IZhO19_segments)C++20
0 / 100
0 ms344 KiB
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ff first 
#define ss second

const int inf = 1e18;

signed main() {

    int n;
    cin >> n;

    vector<int> a(n + 1);
    for(int i = 1; i <= n; i++) cin >> a[i];
    
    vector<pair<int, int>> dp(n + 1, {0, inf});
    vector<int> p(n + 1, 0);
    for(int i = 1; i <= n; i++) {
        p[i] = p[i - 1] + a[i];
    }
    dp[0] = {0, 0};
    for(int i = 1; i <= n; i++) {
        int j = 0;
        // for(int k = 20; k >= 0; k--) {
        //     if(j - (1 << k) >= 0 && dp[j - (1 << k)].ff == dp[j].ff)
        //         j -= (1 << k);
        // }
        while(j > 0 && dp[j].ff == dp[j - 1].ff) j--;
        // if(dp[j].ss > p[i] - p[j]) {
        //     dp[i] = {dp[i - 1].ff, dp[i - 1].ss + a[i]};
        //     continue;
        // }
        // int l = j, r = i - 1, mid, ans = -1;
        // while(l <= r) {
        //     mid = l + (r - l) / 2;
        //     if(dp[mid].ss <= p[i] - p[mid]) {
        //         ans = mid;
        //         l = mid + 1;
        //     } else r = mid - 1;
        // }
        // dp[i] = {dp[ans].ff + 1, p[i] - p[ans]};
        for(; j < i; j++) {
            int sum = p[i] - p[j];
            if(dp[j].ss > sum) {
                if(dp[i].ff < dp[j].ff) {
                    dp[i] = {dp[j].ff, dp[i].ss + sum};
                } else if(dp[i].ff == dp[j].ff) {
                    dp[i].ss = min(dp[i].ss, sum);
                }
            } else {
                if(dp[i].ff < dp[j].ff + 1) {
                    dp[i] = {dp[j].ff + 1, sum};
                } else if(dp[i].ff == dp[j].ff + 1) {
                    dp[i].ss = min(dp[i].ss, sum);
                }
            }
        }
    }
    cout << dp[n].ff << "\n";




    return 0;
}
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