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답안 #293051

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
293051 2020-09-07T15:50:18 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
53 / 100
 1010 ms 63852 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);
    }
    centroidUsed[c] = 1;
    if(nearChild.empty()) return;
    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; j<LIM; 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 32 ms 26752 KB Output is correct
21 Correct 33 ms 26752 KB Output is correct
22 Correct 36 ms 27004 KB Output is correct
23 Correct 44 ms 27128 KB Output is correct
24 Correct 34 ms 26872 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 34 ms 27008 KB Output is correct
27 Correct 24 ms 26752 KB Output is correct
28 Correct 32 ms 26872 KB Output is correct
29 Correct 29 ms 27008 KB Output is correct
30 Correct 32 ms 27008 KB Output is correct
31 Correct 31 ms 27000 KB Output is correct
32 Correct 35 ms 27008 KB Output is correct
33 Correct 31 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 32 ms 26752 KB Output is correct
21 Correct 33 ms 26752 KB Output is correct
22 Correct 36 ms 27004 KB Output is correct
23 Correct 44 ms 27128 KB Output is correct
24 Correct 34 ms 26872 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 34 ms 27008 KB Output is correct
27 Correct 24 ms 26752 KB Output is correct
28 Correct 32 ms 26872 KB Output is correct
29 Correct 29 ms 27008 KB Output is correct
30 Correct 32 ms 27008 KB Output is correct
31 Correct 31 ms 27000 KB Output is correct
32 Correct 35 ms 27008 KB Output is correct
33 Correct 31 ms 27008 KB Output is correct
34 Correct 498 ms 49016 KB Output is correct
35 Incorrect 582 ms 49272 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 32 ms 26752 KB Output is correct
21 Correct 33 ms 26752 KB Output is correct
22 Correct 36 ms 27004 KB Output is correct
23 Correct 44 ms 27128 KB Output is correct
24 Correct 34 ms 26872 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 34 ms 27008 KB Output is correct
27 Correct 24 ms 26752 KB Output is correct
28 Correct 32 ms 26872 KB Output is correct
29 Correct 29 ms 27008 KB Output is correct
30 Correct 32 ms 27008 KB Output is correct
31 Correct 31 ms 27000 KB Output is correct
32 Correct 35 ms 27008 KB Output is correct
33 Correct 31 ms 27008 KB Output is correct
34 Correct 498 ms 49016 KB Output is correct
35 Incorrect 582 ms 49272 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 550 ms 54368 KB Output is correct
2 Correct 1010 ms 60144 KB Output is correct
3 Incorrect 922 ms 60000 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 622 ms 53744 KB Output is correct
2 Correct 806 ms 53516 KB Output is correct
3 Correct 846 ms 63084 KB Output is correct
4 Correct 804 ms 62572 KB Output is correct
5 Correct 777 ms 58480 KB Output is correct
6 Correct 98 ms 54928 KB Output is correct
7 Correct 847 ms 63092 KB Output is correct
8 Correct 180 ms 51828 KB Output is correct
9 Correct 416 ms 50928 KB Output is correct
10 Correct 452 ms 63212 KB Output is correct
11 Correct 653 ms 63852 KB Output is correct
12 Correct 632 ms 63852 KB Output is correct
13 Correct 922 ms 63216 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 32 ms 26752 KB Output is correct
21 Correct 33 ms 26752 KB Output is correct
22 Correct 36 ms 27004 KB Output is correct
23 Correct 44 ms 27128 KB Output is correct
24 Correct 34 ms 26872 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 34 ms 27008 KB Output is correct
27 Correct 24 ms 26752 KB Output is correct
28 Correct 32 ms 26872 KB Output is correct
29 Correct 29 ms 27008 KB Output is correct
30 Correct 32 ms 27008 KB Output is correct
31 Correct 31 ms 27000 KB Output is correct
32 Correct 35 ms 27008 KB Output is correct
33 Correct 31 ms 27008 KB Output is correct
34 Correct 498 ms 49016 KB Output is correct
35 Incorrect 582 ms 49272 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 18 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 19 ms 25600 KB Output is correct
6 Correct 18 ms 25624 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25728 KB Output is correct
11 Correct 18 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 18 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 19 ms 25728 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 32 ms 26752 KB Output is correct
21 Correct 33 ms 26752 KB Output is correct
22 Correct 36 ms 27004 KB Output is correct
23 Correct 44 ms 27128 KB Output is correct
24 Correct 34 ms 26872 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 34 ms 27008 KB Output is correct
27 Correct 24 ms 26752 KB Output is correct
28 Correct 32 ms 26872 KB Output is correct
29 Correct 29 ms 27008 KB Output is correct
30 Correct 32 ms 27008 KB Output is correct
31 Correct 31 ms 27000 KB Output is correct
32 Correct 35 ms 27008 KB Output is correct
33 Correct 31 ms 27008 KB Output is correct
34 Correct 498 ms 49016 KB Output is correct
35 Incorrect 582 ms 49272 KB Output isn't correct
36 Halted 0 ms 0 KB -