Submission #46736

#	Time	Username	Problem	Language	Result	Execution time	Memory
46736		qoo2p5	Rope (JOI17_rope)	C++14	80 / 100	2550 ms	76752 KiB

rope

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int INF = (int) 1e9 + 1e6 + 123;
const ll LINF = (ll) 1e18 + 1e9 + 123;

#define rep(i, s, t) for (auto i = (s); i < (t); ++(i))
#define per(i, s, t) for (auto i = (s); i >= (t); --(i))
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define mp make_pair
#define pb push_back

bool mini(auto &x, const auto &y) {
    if (y < x) {
        x = y;
        return 1;
    }
    return 0;
}

bool maxi(auto &x, const auto &y) {
    if (y > x) {
        x = y;
        return 1;
    }
    return 0;
}

void run();

int main() {
    //~ ios::sync_with_stdio(0);
    //~ cin.tie(0);
    //~ cout.tie(0);
    run();
    return 0;
}

const int N = 1 << 20;

int n, m;
int a[N];
int tree[2 * N + 239];
int cnt_full[N + 239];
vector<int> match[N + 239];

void clr() {
    memset(tree, 0, sizeof tree);
    memset(cnt_full, 0, sizeof cnt_full);
    rep(i, 0, m) {
        match[i].clear();
    }
}

void add(int i, int tl, int tr, int ind, int val) {
    if (tl == tr - 1) {
        tree[i] += val;
        return;
    }
    int tm = (tl + tr) / 2;
    if (ind < tm) add(2 * i + 1, tl, tm, ind, val);
    else add(2 * i + 2, tm, tr, ind, val);
    tree[i] = max(tree[2 * i + 1], tree[2 * i + 2]);
}

void add(int ind, int val) {
    add(0, 0, N, ind, val);
}

int get(int i, int tl, int tr, int l, int r) {
    if (tl >= r || tr <= l) {
        return -INF;
    }
    if (l <= tl && tr <= r) {
        return tree[i];
    }
    int tm = (tl + tr) / 2;
    return max(get(2 * i + 1, tl, tm, l, r), get(2 * i + 2, tm, tr, l, r));
}

int get(int l, int r) {
    return get(0, 0, N, l, r + 1);
}

int ans[N];

void run() {
    scanf("%d%d", &n, &m);
    if (m == 1) {
        cout << "0\n";
        return;
    }
    rep(i, 0, n) {
        scanf("%d", a + i);
        a[i]--;
    }
    rep(i, 0, m) {
        ans[i] = INF;
    }
    
    int qq = 0;
    
    rep(odd_l, 0, 2) {
        rep(odd_r, 0, 2) {
            if ((odd_l + odd_r) % 2 != n % 2) {
                continue;
            }
            
            clr();
            qq++;
            
            for (int i = odd_l; i < n - odd_r; i += 2) {
                if (a[i] != a[i + 1]) {
                    match[a[i]].pb(a[i + 1]);
                    match[a[i + 1]].pb(a[i]);
                } else {
                    cnt_full[a[i]]++;
                }
            }
            
            rep(i, 0, m) {
                add(i, sz(match[i]) + 2 * cnt_full[i] + (odd_l && a[0] == i) + (odd_r && a[n - 1] == i));
            }
            
            rep(i, 0, m) {
                int bonus = (odd_l && a[0] == i) + (odd_r && a[n - 1] == i);
                int we = bonus + cnt_full[i] * 2;
                int simple = 0;
                for (int j : match[i]) {
                    add(j, -1);
                    we++;
                    simple++;
                }
                
                int other = max(get(0, i - 1), get(i + 1, m - 1));
                assert(other >= 0);
                
                if (other == 0) {
                    if (simple > 0) {
                        we--;
                        other++;
                    } else if (bonus > 0) {
                        we--;
                        other++;
                    } else {
                        //~ assert(false);
                    }
                }
                
                mini(ans[i], n - (we + other));
                
                for (int j : match[i]) {
                    add(j, 1);
                }
            }
        }
    }
    
    assert(qq <= 2);
    
    rep(i, 0, m) {
        printf("%d\n", ans[i]);
    }
}

Compilation message (stderr)

rope.cpp: In function 'void run()':
rope.cpp:92:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
rope.cpp:98:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", a + i);
         ~~~~~^~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 30 / 30
• Subtask 3: 10 / 10
• Subtask 4: 25 / 25
• Subtask 5: 0 / 20