oj.uz

Submission #503799

# Submission time Handle Problem Language Result Execution time Memory
503799 2022-01-08T22:57:38 Z tabr Islands (IOI08_islands) C++17
90 / 100
 826 ms 131076 KB 
#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif
 
struct dsu {
    vector<int> p;
    vector<int> sz;
    int n;
 
    dsu(int _n) : n(_n) {
        p.resize(n);
        iota(p.begin(), p.end(), 0);
        sz.assign(n, 1);
    }
 
    inline int get(int x) {
        if (p[x] == x) {
            return x;
        } else {
            return p[x] = get(p[x]);
        }
    }
 
    inline bool unite(int x, int y) {
        x = get(x);
        y = get(y);
        if (x == y) {
            return false;
        }
        if (sz[x] > sz[y]) {
            swap(x, y);
        }
        p[x] = y;
        sz[y] += sz[x];
        return true;
    }
 
    inline bool same(int x, int y) {
        return (get(x) == get(y));
    }
};
 
const int N = (int) 1e6;
int l[N];
int nxt[N];
vector<int> vs[N];
long long dist[N];
long long max_dist[N];
bool cycle[N];
bool was[N];
vector<int> g[N];
int p[N];
pair<int, long long> deq[N];
 
int dsu_get(int x) {
    if (p[x] == x) {
        return x;
    } else {
        return p[x] = dsu_get(p[x]);
    }
}
 
bool dsu_unite(int x, int y) {
    x = dsu_get(x);
    y = dsu_get(y);
    if (x == y) {
        return false;
    }
    p[x] = y;
    return true;
}
 
int x[N];
int order[N];
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    iota(p, p + n, 0);
    for (int i = 0; i < n; i++) {
        int j;
        cin >> j >> l[i];
        j--;
        g[j].emplace_back(i);
        dsu_unite(i, j);
        nxt[i] = j;
    }
    for (int i = 0; i < n; i++) {
        vs[dsu_get(i)].emplace_back(i);
    }
    long long ans = 0;
    for (int i = 0; i < n; i++) {
        if (i != dsu_get(i)) {
            continue;
        }
        int c = i;
        while (!was[c]) {
            was[c] = 1;
            c = nxt[c];
        }
        int u = nxt[c];
        cycle[c] = 1;
        int sz = 1;
        x[0] = c;
        while (u != c) {
            cycle[u] = 1;
            x[sz++] = u;
            u = nxt[u];
        }
        int sz2 = 0;
        int beg = 0;
        int end = 0;
        for (int jj = 0; jj < sz; jj++) {
            int j = x[jj];
            deq[end++].first = j;
            while (beg < end) {
                int v = deq[beg++].first;
                order[sz2++] = v;
                for (int to : g[v]) {
                    if (cycle[to]) {
                        continue;
                    }
                    dist[to] = dist[v] + l[to];
                    deq[end++].first = to;
                }
            }
        }
        long long t = 0;
        for (int j = sz2 - 1; j >= 0; j--) {
            int v = order[j];
            max_dist[v] = max(max_dist[v], dist[v]);
            if (cycle[v]) {
                continue;
            }
            int to = nxt[v];
            t = max(t, max_dist[to] + max_dist[v] - dist[to] * 2);
            max_dist[to] = max(max_dist[to], max_dist[v]);
        }
        long long y = l[c];
        beg = end = 0;
        deq[end++] = make_pair(0, 0);
        for (int jj = 1; jj < sz * 2; jj++) {
            int j = jj % sz;
            if (x[deq[beg].first] == x[j]) {
                beg++;
            }
            t = max(t, y + max_dist[x[j]] - deq[beg].second);
            long long z = y - max_dist[x[j]];
            while (beg < end && deq[end - 1].second >= z) {
                end--;
            }
            y += l[x[j]];
            deq[end++] = make_pair(j, z);
        }
        ans += t;
    }
    cout << ans << '\n';
    return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 47316 KB Output is correct
2 Correct 24 ms 47364 KB Output is correct
3 Correct 23 ms 47308 KB Output is correct
4 Correct 23 ms 47308 KB Output is correct
5 Correct 22 ms 47308 KB Output is correct
6 Correct 22 ms 47272 KB Output is correct
7 Correct 23 ms 47252 KB Output is correct
8 Correct 21 ms 47240 KB Output is correct
9 Correct 22 ms 47308 KB Output is correct
10 Correct 21 ms 47300 KB Output is correct
11 Correct 24 ms 47240 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 47328 KB Output is correct
2 Correct 22 ms 47384 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 47468 KB Output is correct
2 Correct 25 ms 47556 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 48248 KB Output is correct
2 Correct 35 ms 49948 KB Output is correct
3 Correct 29 ms 48932 KB Output is correct
4 Correct 26 ms 48152 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 50980 KB Output is correct
2 Correct 50 ms 53300 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 80 ms 61504 KB Output is correct
2 Correct 85 ms 64184 KB Output is correct
3 Correct 92 ms 66684 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 123 ms 69416 KB Output is correct
2 Correct 150 ms 82392 KB Output is correct
3 Correct 166 ms 91840 KB Output is correct
4 Correct 201 ms 96940 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 236 ms 102228 KB Output is correct
2 Correct 499 ms 113468 KB Output is correct
3 Correct 226 ms 89276 KB Output is correct
4 Correct 282 ms 109588 KB Output is correct
5 Correct 293 ms 113116 KB Output is correct
6 Correct 826 ms 112312 KB Output is correct
7 Correct 303 ms 121020 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 280 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -