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답안 #293029

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
293029 2020-09-07T15:40:01 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
53 / 100
 915 ms 64028 KB 
#include <bits/stdc++.h>
#define LIM 20

using namespace std;

typedef long long ll;
typedef pair<int, int> pi;

struct Path{
    int x, y, idx;
    Path(){}
    Path(int x, int y, int idx): x(x), y(y), idx(idx){}

    bool operator<(const Path &r)const{
        if(x != r.x) return x < r.x;
        if(y != r.x) return y < r.y;
        return idx < r.idx;
    }
};

int n, k;
int par[200002];
vector<int> link[200002];
vector<int> centroidChild[200002];
int subTreeSize[200002];
bool centroidUsed[200002];
int centroidRoot;

int ans, ansX=1, ansY=2;

int getSubTreeSize(int x, int par){
    subTreeSize[x] = 1;
    for(auto &y: link[x]){
        if(y == par || centroidUsed[y]) continue;
        subTreeSize[x] += getSubTreeSize(y, x);
    }
    return subTreeSize[x];
}
int findCentroid(int x){
    int par = 0;
    int treeSize = getSubTreeSize(x, 0);
    while(1){
        int maxTreeSize = 0, maxTreeIdx = -1;
        for(auto &y: link[x]){
            if(centroidUsed[y] || y == par) continue;
            if(subTreeSize[y] > maxTreeSize) maxTreeSize = subTreeSize[y], maxTreeIdx = y;
        }
        if(maxTreeSize <= treeSize / 2){
            break;
        }
        par = x;
        x = maxTreeIdx;
    }
    centroidUsed[x] = 1;
    for(auto &y: link[x]){
        if(centroidUsed[y]) continue;
        int tmp = findCentroid(y);
        centroidChild[x].push_back(tmp);
    }
    return x;
}

int group[200002];
int in[200002], inCnt, depth[200002], inIdx[400002];
vector<pair<int, int> > oppVec[200002];
set<pair<int, int> > sets[200002];
int sparse[400002][LIM];
int cover[400002];

void dfsGroup(int x, int groupNum, int p = 0){
    group[x] = groupNum;
    in[x] = ++inCnt, inIdx[in[x]] = x;
    vector<pair<int, int> >().swap(oppVec[x]);
    sets[x].clear();
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p) continue;
        depth[y] = depth[x]+1;
        dfsGroup(y, groupNum, x);

        inIdx[++inCnt] = x;
    }
}

inline int LCAdepth(int x, int y){
    x = in[x], y = in[y];
    if(x>y) swap(x, y);
    int d = cover[y-x];
    return min(sparse[x][d], sparse[y-(1<<d)+1][d]);
}

inline void put(int x, pair<int, int> p){
    auto it = sets[x].lower_bound(p);
    if(it != sets[x].end()){
        int tmp = depth[x] + LCAdepth(p.first, it->first);
        if(tmp > ans) ans = tmp, ansX = p.second, ansY = it->second;
    }
    if(it != sets[x].begin()){
        it = prev(it);
        int tmp = depth[x] + LCAdepth(p.first, it->first);
        if(tmp > ans) ans = tmp, ansX = p.second, ansY = it->second;
    }
    sets[x].insert(p);
}

void dfsCalc(int x, int p = 0){
    int maxVal = -1, max_loc = -1;
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p) continue;
        dfsCalc(y, x);
        if(maxVal < (int)sets[y].size()) maxVal = sets[y].size(), max_loc = y;
    }

    sets[x].swap(sets[max_loc]);
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p || y==max_loc) continue;
        for(auto p: sets[y]) put(x, p);
        sets[y].clear();
    }
    for(auto p: oppVec[x]){
        put(x, p);
    }
}

void findAnswer(int c, vector<Path> &ust){
    vector<int> nearChild;
    vector<vector<pi> > groupVec;
    vector<vector<Path> > propVec;
    int s;

    for(auto &y: link[c]){
        if(centroidUsed[y]) continue;
        depth[y] = 1; nearChild.push_back(y);
    }
    if(nearChild.empty()) return;
    centroidUsed[c] = 1;
    s = (int)nearChild.size();
    groupVec.resize(s), propVec.resize(s);

    inCnt = depth[c] = 0;
    for(int i=0; i<s; i++){
        dfsGroup(nearChild[i], i);
        inIdx[++inCnt] = c;
    }
    for(int i=inCnt; i>=1; i--){
        sparse[i][0] = depth[inIdx[i]];
        for(int j=1; i+(1<<j)<=inCnt; j++){
            sparse[i][j] = min(sparse[i][j-1], sparse[i+(1<<(j-1))][j-1]);
        }
    }

    for(auto p: ust){
        if(p.x != c && p.y != c && group[p.x] == group[p.y]){
            propVec[group[p.x]].push_back(Path(p.x, p.y, p.idx));
            continue;
        }
        if(p.x != c) groupVec[group[p.x]].push_back({in[p.x], p.idx});
        if(p.y != c) groupVec[group[p.y]].push_back({in[p.y], p.idx});

        if(p.x != c && p.y != c){
            oppVec[p.x].push_back({p.y, p.idx});
            oppVec[p.y].push_back({p.x, p.idx});
        }
    }

    for(int i=0; i<s; i++){ /// check when common subtree is only one
        sort(groupVec[i].begin(), groupVec[i].end());
        for(int j=0; j<(int)groupVec[i].size()-1; j++){
            int tmp = LCAdepth(inIdx[groupVec[i][j].first], inIdx[groupVec[i][j+1].first]);
            if(ans < tmp){
                ans = tmp, ansX = groupVec[i][j].second, ansY = groupVec[i][j+1].second;
            }
        }

        for(int j=0; j<(int)groupVec[i].size(); j++){
            if(j && groupVec[i][j].first == groupVec[i][j-1].first) continue;
            int tmp1 = nearChild[i], tmp2 = inIdx[groupVec[i][j].first];
            if(tmp1 != tmp2) propVec[i].push_back(Path(tmp1, tmp2, groupVec[i][j].second));
        }
    }

    /// check when common subtree is two
    for(int i=0; i<s; i++){
        dfsCalc(nearChild[i]);
    }

    vector<int>().swap(nearChild);
    for(auto &x: groupVec) vector<pi>().swap(x);
    vector<vector<pi> >().swap(groupVec);

    /// propagate to childs
    for(auto &chd: centroidChild[c]){
        findAnswer(chd, propVec[group[chd]]);
        vector<Path>().swap(propVec[group[chd]]);
    }
}

int main(){
    for(int i=1; i<=400000; i++) cover[i] = cover[(i-1)/2]+1;

    scanf("%d %d", &n, &k);

    for(int i=2; i<=n; i++){
        scanf("%d", &par[i]);
        link[i].push_back(par[i]);
        link[par[i]].push_back(i);
    }
    centroidRoot = findCentroid(1);
    memset(centroidUsed, 0, sizeof(centroidUsed));

    vector<Path> st;
    for(int i=1; i<=k; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        st.push_back(Path(x, y, i));
    }

    findAnswer(centroidRoot, st);
    printf("%d\n%d %d", ans, ansX, ansY);
}

Compilation message

sending.cpp: In function 'int main()':
sending.cpp:200:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  200 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
sending.cpp:203:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  203 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:213:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  213 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 30 ms 26752 KB Output is correct
21 Correct 31 ms 26752 KB Output is correct
22 Correct 31 ms 27008 KB Output is correct
23 Correct 33 ms 27008 KB Output is correct
24 Correct 34 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 32 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 26984 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 28 ms 27008 KB Output is correct

Subtask #3
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 30 ms 26752 KB Output is correct
21 Correct 31 ms 26752 KB Output is correct
22 Correct 31 ms 27008 KB Output is correct
23 Correct 33 ms 27008 KB Output is correct
24 Correct 34 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 32 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 26984 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 28 ms 27008 KB Output is correct
34 Correct 423 ms 49016 KB Output is correct
35 Incorrect 473 ms 49016 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 30 ms 26752 KB Output is correct
21 Correct 31 ms 26752 KB Output is correct
22 Correct 31 ms 27008 KB Output is correct
23 Correct 33 ms 27008 KB Output is correct
24 Correct 34 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 32 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 26984 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 28 ms 27008 KB Output is correct
34 Correct 423 ms 49016 KB Output is correct
35 Incorrect 473 ms 49016 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 430 ms 54256 KB Output is correct
2 Correct 915 ms 60268 KB Output is correct
3 Incorrect 788 ms 59884 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #6
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 608 ms 53724 KB Output is correct
2 Correct 702 ms 53448 KB Output is correct
3 Correct 740 ms 63064 KB Output is correct
4 Correct 734 ms 62576 KB Output is correct
5 Correct 667 ms 58352 KB Output is correct
6 Correct 121 ms 54892 KB Output is correct
7 Correct 725 ms 62960 KB Output is correct
8 Correct 157 ms 51860 KB Output is correct
9 Correct 298 ms 50932 KB Output is correct
10 Correct 332 ms 63220 KB Output is correct
11 Correct 508 ms 64028 KB Output is correct
12 Correct 494 ms 63852 KB Output is correct
13 Correct 757 ms 63128 KB Output is correct

Subtask #7
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 30 ms 26752 KB Output is correct
21 Correct 31 ms 26752 KB Output is correct
22 Correct 31 ms 27008 KB Output is correct
23 Correct 33 ms 27008 KB Output is correct
24 Correct 34 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 32 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 26984 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 28 ms 27008 KB Output is correct
34 Correct 423 ms 49016 KB Output is correct
35 Incorrect 473 ms 49016 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 18 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 19 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25600 KB Output is correct
12 Correct 18 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 20 ms 25600 KB Output is correct
16 Correct 18 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 30 ms 26752 KB Output is correct
21 Correct 31 ms 26752 KB Output is correct
22 Correct 31 ms 27008 KB Output is correct
23 Correct 33 ms 27008 KB Output is correct
24 Correct 34 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 32 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 26984 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 28 ms 27008 KB Output is correct
34 Correct 423 ms 49016 KB Output is correct
35 Incorrect 473 ms 49016 KB Output isn't correct
36 Halted 0 ms 0 KB -