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Submission #51842

# Submission time Handle Problem Language Result Execution time Memory
51842 2018-06-21T15:56:39 Z win11905 Islands (IOI08_islands) C++11
100 / 100
 792 ms 61784 KB 
#include <bits/stdc++.h>
#define long long long 
#define pii pair<long, long>
#define x first
#define y second
using namespace std;

const int N = 1e6+5;

int n, deg[N];
long Answer, MaxAll[N];
pii par[N], MaxIn[N];

void solve(int p) {
    vector<pii> V;
    while(deg[p]) V.emplace_back(p, par[p].y), deg[p]--, p = par[p].x;
    int s = V.size();
    deque<pii> Q;
    long dis = V[0].y, pdis = 0, mx = 0;
    for(auto x : V) mx = max(mx, MaxAll[x.x]), mx = max(mx, MaxIn[x.x].x + MaxIn[x.x].y);
    for(int i = 1; i < s; ++i) {
        while(!Q.empty() && Q.back().x < dis + MaxIn[V[i].x].x) Q.pop_back();
        Q.push_back(pii(dis + MaxIn[V[i].x].x, i));
        dis += V[i].y;
    }
    mx = max(mx, MaxIn[V[0].x].x + Q.front().x);
    for(int i = 0; i < s-1; ++i) {
        if(Q.front().y == i+1) Q.pop_front();
        while(!Q.empty() && Q.back().x < dis + MaxIn[V[i].x].x) Q.pop_back();
        Q.push_back(pii(dis + MaxIn[V[i].x].x, i));
        dis += V[i].y, pdis += V[i].y;
        mx = max(mx, MaxIn[V[i+1].x].x + Q.front().x - pdis); 
    }
    Answer += mx;
}

int main() {
    scanf("%d", &n);
    for(int i = 1, a, b; i <= n; ++i) {
        scanf("%d %d", &a, &b);
        par[i] = pii(a, b);
        deg[a]++;
    }
    queue<int> Q;
    for(int i = 1; i <= n; ++i) if(!deg[i]) Q.emplace(i);
    while(!Q.empty()) {
        int now = Q.front(); Q.pop();
        int p = par[now].x, w = par[now].y;
        MaxAll[now] = max(MaxAll[now], MaxIn[now].x + MaxIn[now].y);
        MaxAll[p] = max(MaxAll[p], MaxAll[now]);
        long ret = MaxIn[now].x + w;
        if(ret > MaxIn[p].x) swap(ret, MaxIn[p].x);
        if(ret > MaxIn[p].y) swap(ret, MaxIn[p].y);
        if(!--deg[p]) Q.emplace(p);
    }
    for(int i = 1; i <= n; ++i) if(deg[i]) solve(i);
    printf("%lld\n", Answer);
}

Compilation message

islands.cpp: In function 'int main()':
islands.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
islands.cpp:40:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 488 KB Output is correct
3 Correct 2 ms 488 KB Output is correct
4 Correct 3 ms 488 KB Output is correct
5 Correct 2 ms 488 KB Output is correct
6 Correct 2 ms 612 KB Output is correct
7 Correct 3 ms 612 KB Output is correct
8 Correct 3 ms 612 KB Output is correct
9 Correct 2 ms 612 KB Output is correct
10 Correct 3 ms 652 KB Output is correct
11 Correct 3 ms 652 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 652 KB Output is correct
2 Correct 3 ms 652 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 704 KB Output is correct
2 Correct 4 ms 752 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 1260 KB Output is correct
2 Correct 15 ms 2540 KB Output is correct
3 Correct 16 ms 2540 KB Output is correct
4 Correct 6 ms 2540 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 3448 KB Output is correct
2 Correct 44 ms 5188 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 146 ms 10064 KB Output is correct
2 Correct 105 ms 10380 KB Output is correct
3 Correct 113 ms 15876 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 138 ms 16636 KB Output is correct
2 Correct 210 ms 27284 KB Output is correct
3 Correct 178 ms 27284 KB Output is correct
4 Correct 257 ms 37100 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 379 ms 37100 KB Output is correct
2 Correct 486 ms 44140 KB Output is correct
3 Correct 395 ms 44140 KB Output is correct
4 Correct 382 ms 53140 KB Output is correct
5 Correct 354 ms 54036 KB Output is correct
6 Correct 792 ms 54036 KB Output is correct
7 Correct 524 ms 61784 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 556 ms 61784 KB Output is correct
2 Correct 403 ms 61784 KB Output is correct
3 Correct 559 ms 61784 KB Output is correct
4 Correct 436 ms 61784 KB Output is correct
5 Correct 344 ms 61784 KB Output is correct
6 Correct 363 ms 61784 KB Output is correct
7 Correct 679 ms 61784 KB Output is correct