oj.uz

Submission #1028283

# Submission time Handle Problem Language Result Execution time Memory
1028283 2024-07-19T15:49:32 Z anango Boarding Passes (BOI22_passes) C++17
30 / 100
 31 ms 14228 KB 
#include <bits/stdc++.h>
#define int long long
using namespace std;
int INF = 1LL<<62;

void solve() {

    string S; cin >> S;
    int n = S.size();
    vector<int> ar(n); for (int i=0; i<n; i++) ar[i] = (S[i]-'A');
    int G = *max_element(ar.begin(), ar.end()); G++;
    int pref[n+1][G]; //count of character c, before index i
    int suff[n+1][G]; //count of character c, after or equal to index i
    for (int i=0; i<=n; i++) {
        for (int j=0; j<G; j++) {
            pref[i][j] = suff[i][j] = 0;
        }
    }
    for (int i=0; i<n; i++) {
        for (int j=0; j<=G; j++) {
            if (j==ar[i]) {
                pref[i+1][j] = pref[i][j]+1;
            }
            else {
                pref[i+1][j] = pref[i][j];
            }
        }
    }
    
    for (int i=n-1; i>=0; i--) {
        for (int j=0; j<G; j++) {
            if (j==ar[i]) {
                suff[i][j] = suff[i+1][j]+1;
            }
            else {
                suff[i][j] = suff[i+1][j];
            }
        }
    }
    //everyone before L boards from the front, everyone after or equal to it boards from the back. 
    vector<vector<int>> counts(G,vector<int>(G,0));     //counts[i][j] = sum of subsequences of (i,j) before l, and subsequences of (j,i) after L
    //counts[i][j] = sum of pref[k][j] for k<=L and ar[k]=i, and analogous expression for the suffix
    //first, get initial count values (for everyone boarding from the back)
    //and assuming that these are already boarded since the back breaker may not be the same for each group - that was false assumption
    //so precomp counts then ternary search on the breakpoint
    for (int j=0; j<G; j++) {
        for (int k=0; k<n; k++) {
            int i = ar[k];
            //cout << "adding " << i <<" " << j <<" " << k <<" " << j << " " << suff[k][j] << endl;
            counts[i][j] += suff[k+1][j];
        }
    }
    vector<vector<vector<int>>> acounts;
    acounts.push_back(counts);
    for (int L=0; L<n; L++) {

        //counts[i][j] = number of swaps required if i goes after j



        //transfer L to the right
        int cur = ar[L];
        for (int j=0; j<G; j++) {
            int delta = suff[L+1][j];
            int delta2 = pref[L][j];
            counts[cur][j] -= delta-delta2;
        }
        acounts.push_back(counts);
        
        /*cout << "TRANSFERRED TO " << L+1 << endl;
        for (int i=0; i<G; i++) {
            for (int j=0; j<G; j++) {
                cout << i <<" " << j <<" " << counts[i][j] << endl;
            }
        }
        cout << endl;*/
    }
    vector<int> dp;
    dp=vector<int>(1<<G,INF); //dp[mask] = min cost if this mask is at the beginning of the ordering
    dp[0] = 0;
    for (int mask=0; mask<1<<G; mask++) {
        for (int addon=0; addon<G; addon++) {
            if (mask&(1<<addon)) continue;
            int l = 0; int r = n;
            vector<pair<int,int>> costs;
            while (l<r) {
                int m1,m2;
                if (r-l>10) {
                    m1 = l+(r-l)/5;
                    m2 = r-(r-l)/5;
                }
                else {
                    m1 = l;
                    m2 = r;
                }
                int am1 = 0;
                for (int j=0; j<G; j++) {
                    if (mask&(1<<j)) {
                        am1+=2*acounts[m1][addon][j];
                    }
                    if (j==addon) {
                        am1+=acounts[m1][addon][j];
                    }
                }
                int am2 = 0;
                for (int j=0; j<G; j++) {
                    if (mask&(1<<j)) {
                        am2+=2*acounts[m2][addon][j];
                    }
                    if (j==addon) {
                        am2+=acounts[m2][addon][j];
                    }
                }
                costs.push_back({m1,am1});
                costs.push_back({m2,am2});
                //cout << "adding " << mask <<" " << addon <<" " << l <<" " << r <<" " << m1 <<" " << m2 <<" " << am1 <<" " << am2 << endl;
                if (am1>am2) {
                    l=m1+1; r=r;
                }
                else if (am1<am2) {
                    l=l; r=m2-1;
                }
                else {
                    l=m1+1; r=m2;
                }
                //cout << mask <<" " << addon <<" " << al <<endl;
            }
            sort(costs.begin(), costs.end());
            costs.erase(unique(costs.begin(), costs.end()),costs.end());
            /*for (auto i:costs) {
                cout << i.first <<" " << i.second << endl;
            }*/
            int dec=0;
            int minimum=INF;
            for (int i=0; i<((int)costs.size())-1; i++) {
                if (costs[i].second<costs[i+1].second) dec=1;
                if (costs[i].second>costs[i+1].second && dec) assert(0==1);
                minimum=min(minimum,costs[i].second);
            }
            int al = 0;
            for (int j=0; j<G; j++) {
                if (mask&(1<<j)) {
                    al+=2*acounts[l][addon][j];
                }
                if (j==addon) {
                    al+=acounts[l][addon][j];
                }
            }
            //assert(al==minimum);
            dp[mask | (1<<addon)] = min(dp[mask | (1<<addon)],dp[mask]+al);
        }
    }
    int ans=dp[(1<<G)-1];

    int a2 = ans/2;
    cout << a2;
    if (ans%2==1) cout << ".50";
    cout << endl;
}

signed main() {
    int local=0;
    if (local) {
        // for getting input from input.txt
        freopen("input.txt", "r", stdin);
        // for writing output to output.txt
        freopen("output.txt", "w", stdout);
    }
    /*#ifdef ONLINE_JUDGE
    	ios_base::sync_with_stdio(false);
    	cin.tie(NULL);
    #endif*/ //fast IO
    solve();
    
}

Compilation message

passes.cpp: In function 'int main()':
passes.cpp:165:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  165 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
passes.cpp:167:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  167 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB found '100800.5000000000', expected '100800.5000000000', error '0.0000000000'
2 Correct 0 ms 348 KB found '0.0000000000', expected '0.0000000000', error '-0.0000000000'
3 Correct 0 ms 348 KB found '0.0000000000', expected '0.0000000000', error '-0.0000000000'
4 Correct 0 ms 348 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
5 Correct 0 ms 348 KB found '124002.0000000000', expected '124002.0000000000', error '0.0000000000'
6 Correct 11 ms 9488 KB found '772893586.0000000000', expected '772893586.0000000000', error '0.0000000000'
7 Correct 13 ms 10764 KB found '1100977812.5000000000', expected '1100977812.5000000000', error '0.0000000000'
8 Correct 15 ms 11528 KB found '1249950000.5000000000', expected '1249950000.5000000000', error '0.0000000000'
9 Correct 21 ms 11472 KB found '1249975000.0000000000', expected '1249975000.0000000000', error '0.0000000000'

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
2 Correct 1 ms 348 KB found '1225.0000000000', expected '1225.0000000000', error '0.0000000000'
3 Correct 1 ms 348 KB found '1023.0000000000', expected '1023.0000000000', error '0.0000000000'
4 Correct 1 ms 508 KB found '294.0000000000', expected '294.0000000000', error '0.0000000000'
5 Correct 1 ms 348 KB found '1087.0000000000', expected '1087.0000000000', error '0.0000000000'
6 Correct 1 ms 348 KB found '1.5000000000', expected '1.5000000000', error '0.0000000000'
7 Correct 1 ms 348 KB found '703.0000000000', expected '703.0000000000', error '0.0000000000'
8 Correct 1 ms 348 KB found '55.5000000000', expected '55.5000000000', error '0.0000000000'
9 Correct 1 ms 348 KB found '56.0000000000', expected '56.0000000000', error '0.0000000000'
10 Correct 1 ms 348 KB found '45.0000000000', expected '45.0000000000', error '0.0000000000'
11 Correct 1 ms 348 KB found '66.5000000000', expected '66.5000000000', error '0.0000000000'
12 Correct 1 ms 348 KB found '67.0000000000', expected '67.0000000000', error '0.0000000000'
13 Correct 1 ms 348 KB found '66.0000000000', expected '66.0000000000', error '0.0000000000'
14 Correct 1 ms 348 KB found '47.0000000000', expected '47.0000000000', error '0.0000000000'
15 Correct 1 ms 348 KB found '50.0000000000', expected '50.0000000000', error '0.0000000000'
16 Correct 1 ms 348 KB found '49.0000000000', expected '49.0000000000', error '0.0000000000'
17 Correct 1 ms 348 KB found '57.0000000000', expected '57.0000000000', error '0.0000000000'

Subtask #3
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
2 Correct 1 ms 348 KB found '1225.0000000000', expected '1225.0000000000', error '0.0000000000'
3 Correct 1 ms 348 KB found '1023.0000000000', expected '1023.0000000000', error '0.0000000000'
4 Correct 1 ms 508 KB found '294.0000000000', expected '294.0000000000', error '0.0000000000'
5 Correct 1 ms 348 KB found '1087.0000000000', expected '1087.0000000000', error '0.0000000000'
6 Correct 1 ms 348 KB found '1.5000000000', expected '1.5000000000', error '0.0000000000'
7 Correct 1 ms 348 KB found '703.0000000000', expected '703.0000000000', error '0.0000000000'
8 Correct 1 ms 348 KB found '55.5000000000', expected '55.5000000000', error '0.0000000000'
9 Correct 1 ms 348 KB found '56.0000000000', expected '56.0000000000', error '0.0000000000'
10 Correct 1 ms 348 KB found '45.0000000000', expected '45.0000000000', error '0.0000000000'
11 Correct 1 ms 348 KB found '66.5000000000', expected '66.5000000000', error '0.0000000000'
12 Correct 1 ms 348 KB found '67.0000000000', expected '67.0000000000', error '0.0000000000'
13 Correct 1 ms 348 KB found '66.0000000000', expected '66.0000000000', error '0.0000000000'
14 Correct 1 ms 348 KB found '47.0000000000', expected '47.0000000000', error '0.0000000000'
15 Correct 1 ms 348 KB found '50.0000000000', expected '50.0000000000', error '0.0000000000'
16 Correct 1 ms 348 KB found '49.0000000000', expected '49.0000000000', error '0.0000000000'
17 Correct 1 ms 348 KB found '57.0000000000', expected '57.0000000000', error '0.0000000000'
18 Correct 0 ms 348 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
19 Correct 0 ms 344 KB found '1225.0000000000', expected '1225.0000000000', error '0.0000000000'
20 Correct 1 ms 348 KB found '1023.0000000000', expected '1023.0000000000', error '0.0000000000'
21 Correct 1 ms 348 KB found '294.0000000000', expected '294.0000000000', error '0.0000000000'
22 Correct 1 ms 344 KB found '1087.0000000000', expected '1087.0000000000', error '0.0000000000'
23 Correct 1 ms 348 KB found '1.5000000000', expected '1.5000000000', error '0.0000000000'
24 Correct 1 ms 348 KB found '703.0000000000', expected '703.0000000000', error '0.0000000000'
25 Correct 1 ms 348 KB found '55.5000000000', expected '55.5000000000', error '0.0000000000'
26 Correct 1 ms 348 KB found '56.0000000000', expected '56.0000000000', error '0.0000000000'
27 Correct 1 ms 344 KB found '45.0000000000', expected '45.0000000000', error '0.0000000000'
28 Correct 1 ms 348 KB found '66.5000000000', expected '66.5000000000', error '0.0000000000'
29 Correct 1 ms 348 KB found '67.0000000000', expected '67.0000000000', error '0.0000000000'
30 Correct 1 ms 348 KB found '66.0000000000', expected '66.0000000000', error '0.0000000000'
31 Correct 1 ms 348 KB found '47.0000000000', expected '47.0000000000', error '0.0000000000'
32 Correct 1 ms 348 KB found '50.0000000000', expected '50.0000000000', error '0.0000000000'
33 Correct 1 ms 348 KB found '49.0000000000', expected '49.0000000000', error '0.0000000000'
34 Correct 1 ms 348 KB found '57.0000000000', expected '57.0000000000', error '0.0000000000'
35 Correct 8 ms 10260 KB found '12497500.0000000000', expected '12497500.0000000000', error '0.0000000000'
36 Correct 9 ms 10136 KB found '12495000.5000000000', expected '12495000.5000000000', error '0.0000000000'
37 Incorrect 31 ms 14228 KB 1st numbers differ - expected: '12223392.0000000000', found: '12223397.0000000000', error = '0.0000004091'
38 Halted 0 ms 0 KB -

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB found '100800.5000000000', expected '100800.5000000000', error '0.0000000000'
2 Correct 0 ms 348 KB found '0.0000000000', expected '0.0000000000', error '-0.0000000000'
3 Correct 0 ms 348 KB found '0.0000000000', expected '0.0000000000', error '-0.0000000000'
4 Correct 0 ms 348 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
5 Correct 0 ms 348 KB found '124002.0000000000', expected '124002.0000000000', error '0.0000000000'
6 Correct 11 ms 9488 KB found '772893586.0000000000', expected '772893586.0000000000', error '0.0000000000'
7 Correct 13 ms 10764 KB found '1100977812.5000000000', expected '1100977812.5000000000', error '0.0000000000'
8 Correct 15 ms 11528 KB found '1249950000.5000000000', expected '1249950000.5000000000', error '0.0000000000'
9 Correct 21 ms 11472 KB found '1249975000.0000000000', expected '1249975000.0000000000', error '0.0000000000'
10 Correct 0 ms 344 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
11 Correct 1 ms 348 KB found '1225.0000000000', expected '1225.0000000000', error '0.0000000000'
12 Correct 1 ms 348 KB found '1023.0000000000', expected '1023.0000000000', error '0.0000000000'
13 Correct 1 ms 508 KB found '294.0000000000', expected '294.0000000000', error '0.0000000000'
14 Correct 1 ms 348 KB found '1087.0000000000', expected '1087.0000000000', error '0.0000000000'
15 Correct 1 ms 348 KB found '1.5000000000', expected '1.5000000000', error '0.0000000000'
16 Correct 1 ms 348 KB found '703.0000000000', expected '703.0000000000', error '0.0000000000'
17 Correct 1 ms 348 KB found '55.5000000000', expected '55.5000000000', error '0.0000000000'
18 Correct 1 ms 348 KB found '56.0000000000', expected '56.0000000000', error '0.0000000000'
19 Correct 1 ms 348 KB found '45.0000000000', expected '45.0000000000', error '0.0000000000'
20 Correct 1 ms 348 KB found '66.5000000000', expected '66.5000000000', error '0.0000000000'
21 Correct 1 ms 348 KB found '67.0000000000', expected '67.0000000000', error '0.0000000000'
22 Correct 1 ms 348 KB found '66.0000000000', expected '66.0000000000', error '0.0000000000'
23 Correct 1 ms 348 KB found '47.0000000000', expected '47.0000000000', error '0.0000000000'
24 Correct 1 ms 348 KB found '50.0000000000', expected '50.0000000000', error '0.0000000000'
25 Correct 1 ms 348 KB found '49.0000000000', expected '49.0000000000', error '0.0000000000'
26 Correct 1 ms 348 KB found '57.0000000000', expected '57.0000000000', error '0.0000000000'
27 Correct 0 ms 348 KB found '1.0000000000', expected '1.0000000000', error '0.0000000000'
28 Correct 0 ms 344 KB found '1225.0000000000', expected '1225.0000000000', error '0.0000000000'
29 Correct 1 ms 348 KB found '1023.0000000000', expected '1023.0000000000', error '0.0000000000'
30 Correct 1 ms 348 KB found '294.0000000000', expected '294.0000000000', error '0.0000000000'
31 Correct 1 ms 344 KB found '1087.0000000000', expected '1087.0000000000', error '0.0000000000'
32 Correct 1 ms 348 KB found '1.5000000000', expected '1.5000000000', error '0.0000000000'
33 Correct 1 ms 348 KB found '703.0000000000', expected '703.0000000000', error '0.0000000000'
34 Correct 1 ms 348 KB found '55.5000000000', expected '55.5000000000', error '0.0000000000'
35 Correct 1 ms 348 KB found '56.0000000000', expected '56.0000000000', error '0.0000000000'
36 Correct 1 ms 344 KB found '45.0000000000', expected '45.0000000000', error '0.0000000000'
37 Correct 1 ms 348 KB found '66.5000000000', expected '66.5000000000', error '0.0000000000'
38 Correct 1 ms 348 KB found '67.0000000000', expected '67.0000000000', error '0.0000000000'
39 Correct 1 ms 348 KB found '66.0000000000', expected '66.0000000000', error '0.0000000000'
40 Correct 1 ms 348 KB found '47.0000000000', expected '47.0000000000', error '0.0000000000'
41 Correct 1 ms 348 KB found '50.0000000000', expected '50.0000000000', error '0.0000000000'
42 Correct 1 ms 348 KB found '49.0000000000', expected '49.0000000000', error '0.0000000000'
43 Correct 1 ms 348 KB found '57.0000000000', expected '57.0000000000', error '0.0000000000'
44 Correct 8 ms 10260 KB found '12497500.0000000000', expected '12497500.0000000000', error '0.0000000000'
45 Correct 9 ms 10136 KB found '12495000.5000000000', expected '12495000.5000000000', error '0.0000000000'
46 Incorrect 31 ms 14228 KB 1st numbers differ - expected: '12223392.0000000000', found: '12223397.0000000000', error = '0.0000004091'
47 Halted 0 ms 0 KB -