oj.uz

Submission #84725

# Submission time Handle Problem Language Result Execution time Memory
84725 2018-11-17T03:51:54 Z updown1 Islands (IOI08_islands) C++17
80 / 100
 1318 ms 132096 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define For(i, a, b) for(int i=a; i<b; i++)
#define ffi For(i, 0, N)
#define ffj For(j, 0, M)
#define ffa ffi ffj
#define s <<" "<<
#define c <<" : "<<
#define w cout
#define e endl//"\n"
#define pb push_back
#define mp make_pair
#define a first
#define b second
//#define int ll
const int MAXN=1000000;
///500,000,000
int N, comp[MAXN], cat, nonn[MAXN], st[MAXN], nd[MAXN];
ll siz[MAXN], out, ns[MAXN], pre1[MAXN], pre2[MAXN], suf1[MAXN], suf2[MAXN], ans[MAXN];
bool vis[MAXN], cyc[MAXN];
queue<int> next1;
vector<pair<int, int> > adj[MAXN]; /// (node, cost)

void go(int at) {
    if (comp[at] != -1) return;
    comp[at] = cat;
    for (auto i: adj[at]) go(i.a);
}
void calc_size(int at) {
    if (vis[at]) return;
    vis[at] = true;
    if (adj[at].size() == 1) return;
    ll b1 = 0, b2 = 0;
    for (auto i: adj[at]) if (!cyc[i.a] && !vis[i.a]) {
        calc_size(i.a);
        siz[at] = max(siz[at], i.b+siz[i.a]);
        if (siz[i.a]+i.b >= b1) {b2 = b1; b1 = i.b+siz[i.a];}
        else if (siz[i.a]+i.b > b2) {b2 = i.b+siz[i.a];}
    }
    //w<< at+1 c b1 s b2<<e;
    ans[comp[at]] = max(ans[comp[at]], b1+b2);
}
ll solve (int x) {
    ll ret = 0;
    int loc = 0; int at = st[x];
    //w<< "comp" s x <<e;
    while (at != st[x] || loc == 0) {
        //w<< at+1<<e;
        ns[loc] = siz[at];
        vis[at] = true;
        bool found = false;
        for (auto i: adj[at]) if (!vis[i.a]) {
            nd[loc] = i.b;
            at = i.a;
            found = true;
            break;
        }
        if (!found) {
            vis[st[x]] = false;
            for (auto i: adj[at]) if (!vis[i.a]) {
                nd[loc] = i.b;
                at = i.a;
            }
        }
        loc++;
    }
    assert(loc != 1); /// edge from x to x
    //For (i, 0, loc) w<< ns[i] s nd[i]<<e;
    pre1[0] = ns[0];
    ll curr = 0;
    For (i, 1, loc) {
        curr += nd[i-1];
        pre1[i] = max(pre1[i-1], curr+ns[i]);
        ret = max(ret, curr+ns[0] + ns[i]);
    }
    //For (i, 0, loc) w<< "pre1" s i c pre1[i]<<e;
    suf1[loc-1] = nd[loc-1] + ns[loc-1];
    curr = nd[loc-1];
    for (int i=loc-2; i>=1; i--) {
        curr += nd[i];
        suf1[i] = max(suf1[i+1], curr+ns[i]);
    }
    //For (i, 0, loc) w<< "suf1" s i c suf1[i]<<e;
    For (i, 0, loc-1) ret = max(ret, pre1[i] + suf1[i+1]);
    //w<< "from pass 1, ret =" s ret<<e;


    pre2[0] = ns[0];
    For (i, 1, loc) pre2[i] = max(pre2[i-1]+nd[i-1], ns[i]);
    //For (i, 0, loc) w<< "pre2" s i c pre2[i]<<e;
    suf2[loc-1] = 0;
    for (int i=loc-2; i>=0; i--) suf2[i] = max(suf2[i+1]+nd[i], ns[i+1]+nd[i]);
    //For (i, 0, loc) w<< "suf2" s i c suf2[i]<<e;
    For (i, 0, loc) ret = max(ret, pre2[i]+suf2[i]);
    //w<< "after pass 2, ret =" s ret<<e;
    return max(ret, ans[x]);
}

main() {
    //ifstream cin("test.in");
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> N;
    ffi {cyc[i] = true; comp[i] = -1; int b, d; cin >> b >> d; b--; adj[i].pb(mp(b, d)); adj[b].pb(mp(i, d));}
    ffi if (comp[i] == -1) {go(i); cat++;}
    ffi if (adj[i].size() == 1) next1.push(i);
    while (!next1.empty()) {
        int at = next1.front(); next1.pop();
        if (!cyc[at]) continue;
        if (nonn[at] == adj[at].size()-1) {
            cyc[at] = false;
            for (auto i: adj[at]) {
                nonn[i.a]++;
                if (cyc[i.a]) next1.push(i.a);
            }
        }
    }
    //ffi w<< i+1 c cyc[i]<<e;
    ffi if (cyc[i]) {st[comp[i]] = i; calc_size(i);}
    //ffi w<< i+1 c siz[i]<<e;
    ffi {
        vis[i] = false;
        if (!cyc[i]) vis[i] = true;
    }
    For (i, 0, cat) out += solve(i);
    w<< out <<e;
}

Compilation message

islands.cpp:100:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
islands.cpp: In function 'int main()':
islands.cpp:110:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (nonn[at] == adj[at].size()-1) {
             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23928 KB Output is correct
2 Correct 23 ms 24064 KB Output is correct
3 Correct 24 ms 24064 KB Output is correct
4 Correct 23 ms 24168 KB Output is correct
5 Correct 23 ms 24168 KB Output is correct
6 Correct 23 ms 24308 KB Output is correct
7 Correct 26 ms 24312 KB Output is correct
8 Correct 25 ms 24312 KB Output is correct
9 Correct 23 ms 24312 KB Output is correct
10 Correct 27 ms 24312 KB Output is correct
11 Correct 23 ms 24436 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 24444 KB Output is correct
2 Correct 28 ms 24472 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 24636 KB Output is correct
2 Correct 25 ms 24812 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 25752 KB Output is correct
2 Correct 48 ms 28268 KB Output is correct
3 Correct 37 ms 28268 KB Output is correct
4 Correct 34 ms 28268 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 56 ms 30540 KB Output is correct
2 Correct 74 ms 33952 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 145 ms 42680 KB Output is correct
2 Correct 140 ms 47492 KB Output is correct
3 Correct 173 ms 61176 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 214 ms 63232 KB Output is correct
2 Correct 289 ms 90464 KB Output is correct
3 Correct 311 ms 95184 KB Output is correct
4 Correct 403 ms 126612 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 514 ms 126612 KB Output is correct
2 Runtime error 1318 ms 132096 KB Memory limit exceeded: We have a known bug that the memory usage is measured incorrectly (possibly because of Meltdown/Spectre patch), so your solution may be correct. Please submit again. Sorry for the inconvenience.
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 576 ms 132096 KB Execution killed with signal 9 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -