Submission #146652

#	Time	Username	Problem	Language	Result	Execution time	Memory
146652		tri	Ancient Books (IOI17_books)	C++14	50 / 100	344 ms	74628 KiB

books

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;

#define pb push_back
#define f first
#define s second

namespace debug {
    const int DEBUG = false;

    template<class T1, class T2>
    void pr(const pair<T1, T2> &x);

    template<class T, size_t SZ>
    void pr(const array<T, SZ> &x);

    template<class T>
    void pr(const vector<T> &x);

    template<class T>
    void pr(const set<T> &x);

    template<class T1, class T2>
    void pr(const map<T1, T2> &x);

    template<class T>
    void pr(const T &x) { if (DEBUG) cout << x; }

    template<class T, class... Ts>
    void pr(const T &first, const Ts &... rest) { pr(first), pr(rest...); }

    template<class T1, class T2>
    void pr(const pair<T1, T2> &x) { pr("{", x.f, ", ", x.s, "}"); }

    template<class T>
    void prIn(const T &x) {
        pr("{");
        bool fst = 1;
        for (auto &a : x) {
            pr(fst ? "" : ", ", a), fst = 0;
        }
        pr("}");
    }

    template<class T, size_t SZ>
    void pr(const array<T, SZ> &x) { prIn(x); }

    template<class T>
    void pr(const vector<T> &x) { prIn(x); }

    template<class T>
    void pr(const set<T> &x) { prIn(x); }

    template<class T1, class T2>
    void pr(const map<T1, T2> &x) { prIn(x); }

    void ps() { pr("\n"), cout << flush; }

    template<class Arg, class... Args>
    void ps(const Arg &first, const Args &... rest) {
        pr(first, " ");
        ps(rest...);
    }
}
using namespace debug;


int N;
vi nxt;

ll minimum_walk(vi p, int s) {
    N = p.size();

    // prune
    int l = 0, r = N - 1;
    while (l < s && p[l] == l) {
        l++;
    }
    while (r > s && p[r] == r) {
        r--;
    }

    for (int i = l; i <= r; i++) {
        nxt.pb(p[i] - l);
    }
    N = nxt.size();

    //ps("fin prune");

    ll sum = 0;
    for (int i = 0; i < N; i++) {
        sum += abs(nxt[i] - i);
    }

    vector<vi> groups;
    vi id(N, -1);

    for (int i = 0; i < N; i++) {
        if (id[i] == -1) {
            vi newG;

            int cur = i;
            while (id[cur] == -1) {
                id[cur] = groups.size();
                newG.pb(cur);
                cur = nxt[cur];
            }

            groups.pb(newG);
        }
    }

    //ps("div groups");

    vi lM, rM;
    for (int i = 0; i < groups.size(); i++) {
        int cLM = N, cRM = 0;
        for (int x : groups[i]) {
            cLM = min(cLM, x);
            cRM = max(cRM, x);
        }
        lM.push_back(cLM);
        rM.push_back(cRM);
    }

    //ps("prep");

    sort(lM.begin(), lM.end());

    int visRM = 0;
    int nxtLM = 0;
    while (nxtLM < groups.size()) {
        int cX = lM[nxtLM];
        if (cX > visRM) {
            assert(cX == visRM + 1);
            sum += 2;
        }
        visRM = max(rM[id[cX]], visRM);
        nxtLM++;
    }
    return sum;
}

Compilation message (stderr)

books.cpp: In function 'll minimum_walk(vi, int)':
books.cpp:126:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < groups.size(); i++) {
                     ~~^~~~~~~~~~~~~~~
books.cpp:142:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (nxtLM < groups.size()) {
            ~~~~~~^~~~~~~~~~~~~~~

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