oj.uz

Submission #147249

# Submission time Handle Problem Language Result Execution time Memory
147249 2019-08-28T13:51:25 Z dolphingarlic Koala Game (APIO17_koala) C++14
100 / 100
 69 ms 908 KB 
#include "koala.h"
#include <bits/stdc++.h>
#pragma GCC Optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;

int B[100], R[100];

/*
HELPER FUNCTIONS
*/

bool compare(int a, int b, int N, int W) {
    fill(B, B + N, 0);
    B[a] = B[b] = W;
    playRound(B, R);
    return (R[b] > W);
}
vector<int> mergesort(vector<int> v, int N, int W) {
    if (v.size() == 1) return v;
 
    vector<int> a, b;
    a.insert(a.begin(), v.begin(), v.begin() + (v.size() + 1) / 2);
    b.insert(b.begin(), v.begin() + (v.size() + 1) / 2, v.end());
    a = mergesort(a, N, W), b = mergesort(b, N, W);
 
    vector<int> sorted;
    int aptr = 0, bptr = 0;
    while (aptr < a.size() && bptr < b.size()) {
        if (compare(a[aptr], b[bptr], N, W)) sorted.push_back(a[aptr++]);
        else sorted.push_back(b[bptr++]);
    }
    sorted.insert(sorted.end(), a.begin() + aptr, a.end());
    sorted.insert(sorted.end(), b.begin() + bptr, b.end());
 
    return sorted;
}

void split(vector<int> v, int N, int W, int* P, int l = 1, int r = 100) {
    if (l == r) P[v[0]] = l;
    else {
        int x = min((int)sqrt(2 * l), W / (r - l + 1));

        fill(B, B + N, 0);
        for (int i : v) B[i] = x;

        playRound(B, R);
        vector<int> less, greater;
        for (int i : v) if (R[i] > x) greater.push_back(i);
        else less.push_back(i);

        split(less, N, W, P, l, l + less.size() - 1);
        split(greater, N, W, P, r - greater.size() + 1, r);
    }
}

/*
BEGIN ACTUAL FUNCTIONS
*/

// Assign a single stone to the first cup.
// If Koala picks that cup, it is not the smallest and some other cup has 0.
// Otherwise, cup 0 is the smallest cup.
// Uses 1 turn
int minValue(int N, int W) {
    fill(B, B + N, 0);
    fill(R, R + N, 0);
    B[0] = 1;
    playRound(B, R);
    if (R[0] < 2) return 0;
    else for (int i = 1; i < N; i++) if (!R[i]) return i;
    return -1;
}

// Binary search for the max value.
// Uses like 4 turns
int maxValue(int N, int W) {
    vector<int> v;
    for (int i = 0; i < N; i++) v.push_back(i);
    while (v.size() != 1) {
        int k = W / v.size();
        fill(B, B + N, 0);
        for (int i : v) B[i] = k;
        playRound(B, R);
        v.clear();
        for (int i = 0; i < N; i++) if (R[i] > k) v.push_back(i);
    }
    return v[0];
}

// Assign positions 0 and 1 x stones until Koala treats them differently.
// Binary search for x:
// If both 0 and 1 get > x stones, increase x.
// If both 0 and 1 get < x stones, decrease x.
// Notice how x <= 9 because sum(9..17) > 100.
// Uses like 3 turns
int greaterValue(int N, int W) {
    int l = 1, r = 9;
    while (l != r) {
        int mid = (l + r) / 2;
        B[0] = B[1] = mid;
        playRound(B, R);

        if (R[0] > mid && R[1] > mid) l = mid + 1;
        else if (R[0] <= mid && R[1] <= mid) r = mid - 1;
        else return (R[0] < R[1]);
    }
    B[0] = B[1] = l;
    playRound(B, R);
    return (R[0] < R[1]);
}

// Subtask 4:
// Assign indices i and j 100 stones each to check whether P[i] > P[j].
// Use merge sort to get O(Nlog(N)) <= 700 turns
// Subtask 5:
// We have a recursive strategy that solves a known range [L..R] in
// exactly L + R - 1 moves by splitting [L..R] into [L..k] and [k+1..R]
// for some k in exactly 1 move.
// We do this by assigning each position in the range [L..R]
// x = min(sqrt(2 * L), M / (R - L + 1)) stones and then checking which
// positions Koala has placed > x stones next to after the round.
// We can easily get k this way and we always have 0 < k < L - R + 1
// Uses exactly 99 moves
void allValues(int N, int W, int *P) {
    if (W == 2 * N) {
        vector<int> v;
        for (int i = 0; i < N; i++) v.push_back(i);
        vector<int> sorted = mergesort(v, N, W / 2);
        for (int i = 0; i < N; i++) P[sorted[i]] = i + 1;
    } else {
        vector<int> v;
        for (int i = 0; i < N; i++) v.push_back(i);
        split(v, N, W, P);
    }
}

Compilation message

koala.cpp:3:0: warning: ignoring #pragma GCC Optimize [-Wunknown-pragmas]
 #pragma GCC Optimize("O3")
 
koala.cpp: In function 'std::vector<int> mergesort(std::vector<int>, int, int)':
koala.cpp:29:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (aptr < a.size() && bptr < b.size()) {
            ~~~~~^~~~~~~~~~
koala.cpp:29:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (aptr < a.size() && bptr < b.size()) {
                               ~~~~~^~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 376 KB Output is correct
2 Correct 6 ms 376 KB Output is correct
3 Correct 7 ms 376 KB Output is correct
4 Correct 6 ms 376 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 376 KB Output is correct
2 Correct 18 ms 376 KB Output is correct
3 Correct 16 ms 376 KB Output is correct
4 Correct 16 ms 376 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 61 ms 760 KB Output is correct
2 Correct 69 ms 404 KB Output is correct
3 Correct 59 ms 908 KB Output is correct
4 Correct 60 ms 724 KB Output is correct
5 Correct 60 ms 856 KB Output is correct
6 Correct 60 ms 632 KB Output is correct
7 Correct 59 ms 632 KB Output is correct
8 Correct 60 ms 776 KB Output is correct
9 Correct 60 ms 636 KB Output is correct
10 Correct 59 ms 760 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 376 KB Output is correct
2 Correct 35 ms 376 KB Output is correct
3 Correct 34 ms 504 KB Output is correct
4 Correct 34 ms 376 KB Output is correct
5 Correct 33 ms 376 KB Output is correct
6 Correct 34 ms 376 KB Output is correct
7 Correct 33 ms 376 KB Output is correct
8 Correct 33 ms 376 KB Output is correct
9 Correct 33 ms 376 KB Output is correct
10 Correct 33 ms 376 KB Output is correct
11 Correct 33 ms 376 KB Output is correct
12 Correct 21 ms 384 KB Output is correct
13 Correct 33 ms 376 KB Output is correct
14 Correct 31 ms 376 KB Output is correct
15 Correct 30 ms 376 KB Output is correct
16 Correct 29 ms 376 KB Output is correct
17 Correct 30 ms 376 KB Output is correct
18 Correct 31 ms 376 KB Output is correct
19 Correct 30 ms 376 KB Output is correct
20 Correct 31 ms 376 KB Output is correct

Subtask #5
53.0 / 53.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 6 ms 376 KB Output is correct
3 Correct 5 ms 376 KB Output is correct
4 Correct 5 ms 376 KB Output is correct
5 Correct 5 ms 376 KB Output is correct
6 Correct 5 ms 296 KB Output is correct
7 Correct 5 ms 376 KB Output is correct
8 Correct 5 ms 376 KB Output is correct
9 Correct 5 ms 376 KB Output is correct
10 Correct 5 ms 376 KB Output is correct
11 Correct 6 ms 376 KB Output is correct
12 Correct 6 ms 376 KB Output is correct
13 Correct 5 ms 376 KB Output is correct
14 Correct 5 ms 376 KB Output is correct
15 Correct 5 ms 376 KB Output is correct
16 Correct 6 ms 376 KB Output is correct
17 Correct 5 ms 376 KB Output is correct
18 Correct 5 ms 376 KB Output is correct
19 Correct 6 ms 376 KB Output is correct
20 Correct 6 ms 376 KB Output is correct
21 Correct 5 ms 376 KB Output is correct
22 Correct 5 ms 376 KB Output is correct
23 Correct 5 ms 376 KB Output is correct
24 Correct 6 ms 376 KB Output is correct
25 Correct 5 ms 376 KB Output is correct
26 Correct 6 ms 376 KB Output is correct
27 Correct 5 ms 376 KB Output is correct
28 Correct 6 ms 384 KB Output is correct
29 Correct 6 ms 376 KB Output is correct
30 Correct 5 ms 396 KB Output is correct
31 Correct 5 ms 376 KB Output is correct
32 Correct 5 ms 376 KB Output is correct
33 Correct 6 ms 376 KB Output is correct
34 Correct 6 ms 376 KB Output is correct
35 Correct 5 ms 376 KB Output is correct
36 Correct 5 ms 376 KB Output is correct
37 Correct 5 ms 376 KB Output is correct
38 Correct 5 ms 376 KB Output is correct
39 Correct 5 ms 376 KB Output is correct
40 Correct 5 ms 376 KB Output is correct