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답안 #292989

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
292989 2020-09-07T15:22:28 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
53 / 100
 901 ms 63084 KB 
#include <bits/stdc++.h>
#define LIM 19

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 par = 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==par) 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 par = 0){
    int maxVal = -1, max_loc = -1;
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==par) 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==par || 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){ /// insert into map
            int tmp1 = group[p.x], tmp2 = group[p.y];
            if(tmp1 > tmp2) swap(tmp1, tmp2);
            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 tmpMin = INT_MAX;
            for(int x=groupVec[i][j].first; x<=groupVec[i][j+1].first; x++) tmpMin = min(tmpMin, depth[inIdx[x]]);
            if(ans < tmpMin){
                ans = tmpMin, 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(min(tmp1, tmp2), max(tmp1, tmp2), groupVec[i][j].second));
        }
    }

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

    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:203:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  203 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
sending.cpp:206:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  206 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:216:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  216 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 27 ms 26752 KB Output is correct
21 Correct 39 ms 26744 KB Output is correct
22 Correct 29 ms 27008 KB Output is correct
23 Correct 36 ms 27008 KB Output is correct
24 Correct 29 ms 26880 KB Output is correct
25 Correct 19 ms 26880 KB Output is correct
26 Correct 33 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26624 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 28 ms 27000 KB Output is correct
31 Correct 27 ms 26880 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 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 27 ms 26752 KB Output is correct
21 Correct 39 ms 26744 KB Output is correct
22 Correct 29 ms 27008 KB Output is correct
23 Correct 36 ms 27008 KB Output is correct
24 Correct 29 ms 26880 KB Output is correct
25 Correct 19 ms 26880 KB Output is correct
26 Correct 33 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26624 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 28 ms 27000 KB Output is correct
31 Correct 27 ms 26880 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 48376 KB Output is correct
35 Incorrect 480 ms 48376 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 27 ms 26752 KB Output is correct
21 Correct 39 ms 26744 KB Output is correct
22 Correct 29 ms 27008 KB Output is correct
23 Correct 36 ms 27008 KB Output is correct
24 Correct 29 ms 26880 KB Output is correct
25 Correct 19 ms 26880 KB Output is correct
26 Correct 33 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26624 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 28 ms 27000 KB Output is correct
31 Correct 27 ms 26880 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 48376 KB Output is correct
35 Incorrect 480 ms 48376 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 433 ms 53484 KB Output is correct
2 Correct 901 ms 59504 KB Output is correct
3 Incorrect 830 ms 59108 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 555 ms 53148 KB Output is correct
2 Correct 713 ms 52592 KB Output is correct
3 Correct 720 ms 62324 KB Output is correct
4 Correct 696 ms 61680 KB Output is correct
5 Correct 650 ms 57716 KB Output is correct
6 Correct 95 ms 54124 KB Output is correct
7 Correct 719 ms 62320 KB Output is correct
8 Correct 150 ms 51060 KB Output is correct
9 Correct 297 ms 50288 KB Output is correct
10 Correct 322 ms 62444 KB Output is correct
11 Correct 503 ms 63084 KB Output is correct
12 Correct 485 ms 62956 KB Output is correct
13 Correct 759 ms 62360 KB Output is correct

Subtask #7
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 27 ms 26752 KB Output is correct
21 Correct 39 ms 26744 KB Output is correct
22 Correct 29 ms 27008 KB Output is correct
23 Correct 36 ms 27008 KB Output is correct
24 Correct 29 ms 26880 KB Output is correct
25 Correct 19 ms 26880 KB Output is correct
26 Correct 33 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26624 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 28 ms 27000 KB Output is correct
31 Correct 27 ms 26880 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 48376 KB Output is correct
35 Incorrect 480 ms 48376 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 22 ms 25600 KB Output is correct
4 Correct 17 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 19 ms 25600 KB Output is correct
8 Correct 17 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 22 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 17 ms 25600 KB Output is correct
14 Correct 18 ms 25580 KB Output is correct
15 Correct 17 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 21 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 27 ms 26752 KB Output is correct
21 Correct 39 ms 26744 KB Output is correct
22 Correct 29 ms 27008 KB Output is correct
23 Correct 36 ms 27008 KB Output is correct
24 Correct 29 ms 26880 KB Output is correct
25 Correct 19 ms 26880 KB Output is correct
26 Correct 33 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26624 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 28 ms 27000 KB Output is correct
31 Correct 27 ms 26880 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 48376 KB Output is correct
35 Incorrect 480 ms 48376 KB Output isn't correct
36 Halted 0 ms 0 KB -