Submission #1037857

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037857		Forested	Ancient Books (IOI17_books)	C++17	50 / 100	80 ms	15752 KiB

books

#include <bits/stdc++.h>
using namespace std;
using i32 = int;
using i64 = long long;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
template <typename T>
using VVV = V<VV<T>>;
template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
#define OVERRIDE4(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, l, r) for (i32 i = (i32)(l); i < (i32)(r); ++i)
#define REP(...) OVERRIDE4(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i)
#define PER3(i, l, r) for (i32 i = (i32)(r)-1; i >= (i32)(l); --i)
#define PER(...) OVERRIDE4(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define LEN(x) (i32) size(x)
#define ALL(x) begin(x), end(x)

void dbg(i32 x) { cerr << x; }
void dbg(i64 x) { cerr << x; }
template <typename T, typename U>
void dbg(pair<T, U> p) {
    cerr << "(";
    dbg(p.first);
    cerr << ", ";
    dbg(p.second);
    cerr << ")";
}
template <typename T>
void dbg(V<T> arr) {
    cerr << "[";
    REP(i, LEN(arr)) {
        if (i) {
            cerr << ", ";
        }
        dbg(arr[i]);
    }
    cerr << "]";
}
void debug() { cerr << '\n'; }
template <typename Head, typename... Tail>
void debug(Head head, Tail... tail) {
    dbg(head);
    cerr << ", ";
    debug(tail...);
}
#ifdef DEBUGF
#define DBG(...)                       \
    do {                               \
        cerr << #__VA_ARGS__ << " : "; \
        debug(__VA_ARGS__);            \
    } while (false)
#else
#define DBG(...) (void)0
#endif

#include "books.h"

i32 daitan(const V<i32> &p, i32 s) {
    i32 n = LEN(p);
    VV<i32> loops;
    i32 root = -1;
    {
        V<i32> seen(n, 0);
        REP(i, n) {
            if (seen[i]) {
                continue;
            }
            V<i32> tmp;
            i32 cur = i;
            while (!seen[cur]) {
                seen[cur] = 1;
                tmp.push_back(cur);
                cur = p[cur];
            }
            if (count(ALL(tmp), s) || LEN(tmp) >= 2) {
                loops.emplace_back(tmp);
                if (count(ALL(tmp), s)) root = LEN(loops) - 1;
            }
        }
    }
    i32 k = LEN(loops);
    constexpr i32 INF = 1001001001;
    VV<i32> join(k, V<i32>(k, INF));
    REP(i, k) REP(j, k) {
        for (i32 x : loops[i])
            for (i32 y : loops[j]) {
                i32 py = p[y];
                i32 tmp = abs(x - y) + abs(x - py) - abs(y - py);
                chmin(join[i][j], tmp);
            }
    }
    V<i32> rem(k, 1);
    rem[root] = 0;
    i32 ans = 0;
    REP(iter, k - 1) {
        i32 mn = INF, mnv = -1;
        REP(i, k) {
            if (!rem[i]) {
                continue;
            }
            REP(j, k) {
                if (rem[j]) {
                    continue;
                }
                if (chmin(mn, join[i][j])) {
                    mnv = i;
                }
            }
        }
        ans += mn;
        rem[mnv] = 0;
    }
    REP(i, n) { ans += abs(i - p[i]); }
    return ans;
}

i64 daitan2(const V<i32> &p, i32 s) {
    i32 n = LEN(p);
    V<i32> a(n, 0);
    REP(i, n) {
        i32 x = i, y = p[i];
        if (x > y) {
            swap(x, y);
        }
        a[x] += 1;
        a[y] -= 1;
    }
    REP(i, n - 1) {
        a[i + 1] += a[i];
    }
    i32 mn = s, mx = s;
    REP(i, n) {
        if (a[i]) {
            chmin(mn, i);
            chmax(mx, i + 1);
        }
    }
    i64 ans = 0;
    REP(i, n) {
        ans += abs(i - p[i]);
    }
    REP(i, mn, mx) {
        if (!a[i]) {
            ans += 2;
        }
    }
    return ans;
}

i64 minimum_walk(V<i32> p, i32 s) {
    return daitan2(p, s);
}

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30