Submission #701926

#	Time	Username	Problem	Language	Result	Execution time	Memory
701926		Cyanmond	Gondola (IOI14_gondola)	C++17	75 / 100	32 ms	4820 KiB

gondola

#include "gondola.h"
#include <bits/stdc++.h>

int valid(int n, int inputSeq[]) {
    for (int i = 0; i < n; ++i) {
        --inputSeq[i];
    }
    {
        // double
        std::set<int> s;
        for (int i = 0; i < n; ++i) {
            s.insert(inputSeq[i]);
        }
        if (s.size() != n) {
            return false;
        }
    }
    for (int f = 0; f < n; ++f) {
        if (inputSeq[f] >= n) {
            continue;
        }
        int x = inputSeq[f];
        bool answer = true;
        for (int i = f + 1; i < n; ++i) {
            const int y = (x + 1) % n;
            if (inputSeq[i] < n and y != inputSeq[i]) {
                answer = false;
            }
            x = y;
        }
        return answer;
    }
    return true;
}

//----------------------

int replacement(int n, int gondolaSeq[], int replacementSeq[]) {
    assert(valid(n, gondolaSeq) == 1);
    int maxGondola = 0;
    for (int i = 0; i < n; ++i) {
        maxGondola = std::max(maxGondola, gondolaSeq[i]);
    }
    std::vector<int> gondolaPos(maxGondola + 1, -1);
    for (int i = 0; i < n; ++i) {
        gondolaPos[gondolaSeq[i]] = i;
    }
    std::vector<std::pair<int, int>> eventList;
    for (int i = 0; i < n; ++i) {
        eventList.push_back({gondolaSeq[i], i});
    }
    std::sort(eventList.begin(), eventList.end());
    std::vector<int> answer;
    int spareGondola = n;
    std::vector<int> nowGondolaSeq(n, -1);
    for (int i = 0; i < n; ++i) {
        if (gondolaSeq[i] < n) {
            nowGondolaSeq[i] = gondolaSeq[i];
            int j = (i + 1) % n, lastVal  = nowGondolaSeq[i];
            while (j != i) {
                lastVal = (lastVal + 1) % n;
                nowGondolaSeq[j] = lastVal;
                j = (j + 1) % n;
            }
            break;
        }
    }
    if (nowGondolaSeq[0] == -1) {
        std::iota(nowGondolaSeq.begin(), nowGondolaSeq.end(), 0);
    }
    for (int i = 0; i < n; ++i) {
        const auto [v, pos] = eventList[i];
        if (v < n) {
            continue;
        }
        int &g = nowGondolaSeq[pos];
        while (spareGondola <= v) {
            answer.push_back(g);
            g = spareGondola++;
        }
    }

    // cvr
    for (int i = 0; i < (int)answer.size(); ++i) {
        replacementSeq[i] = answer[i] + 1;
    }
    return (int)answer.size();
}

//----------------------

using i64 = long long;
constexpr i64 mod = 1000000009;
i64 add(i64 a, i64 b) {
    return (a + b) % mod;
}
i64 sub(i64 a, i64 b) {
    return (a + mod - b) % mod;
}
i64 mul(i64 a, i64 b) {
    return (a * b) % mod;
}
void eadd(i64 &a, i64 b) {
    a = add(a, b);
}
void esub(i64 &a, i64 b) {
    a = sub(a, b);
}
void emul(i64 &a, i64 b) {
    a = mul(a, b);
}

i64 moduloPow(i64 a, i64 n) {
    i64 ret = 1;
    while (n != 0) {
        if (n % 2 == 1) {
            emul(ret, a);
        }
        emul(a, a);
        n /= 2;
    }
    return ret;
}

int countReplacement(int n, int inputSeq[]) {
    if (valid(n, inputSeq) == 0) {
        return 0;
    }
    std::vector<int> initSeq(n, -1);
    for (int i = 0; i < n; ++i) {
        if (inputSeq[i] < n) {
            initSeq[i] = inputSeq[i];
            int j = (i + 1) % n, lastVal  = initSeq[i];
            while (j != i) {
                lastVal = (lastVal + 1) % n;
                initSeq[j] = lastVal;
                j = (j + 1) % n;
            }
            break;
        }
    }

    bool isFree = false;
    if (initSeq[0] == -1) {
        std::iota(initSeq.begin(), initSeq.end(), 0);
        isFree = true;
    }
    std::vector<std::pair<int, int>> eventList;
    for (int i = 0; i < n; ++i) {
        eventList.push_back({inputSeq[i], i});
    }
    std::sort(eventList.begin(), eventList.end());
    int lastVal = n - 1;
    i64 answer = 1;
    for (int i = 0; i < n; ++i) {
        const auto [v, pos] = eventList[i];
        if (v < n) {
            continue;
        }
        const int a = n - i, b = v - lastVal- 1;
        const auto k = moduloPow(a, b);
        emul(answer, k);
        lastVal = v;
    }
    
    assert(0 <= answer and answer < mod);
    return (int)answer;
}

Compilation message (stderr)

gondola.cpp: In function 'int valid(int, int*)':
gondola.cpp:14:22: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   14 |         if (s.size() != n) {
      |             ~~~~~~~~~^~~~
gondola.cpp: In function 'int countReplacement(int, int*)':
gondola.cpp:143:10: warning: variable 'isFree' set but not used [-Wunused-but-set-variable]
  143 |     bool isFree = false;
      |          ^~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 10 / 10
• Subtask 4: 5 / 5
• Subtask 5: 10 / 10
• Subtask 6: 20 / 20
• Subtask 7: 5 / 5
• Subtask 8: 15 / 15
• Subtask 9: 0 / 15
• Subtask 10: 0 / 10