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답안 #292885

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
292885 2020-09-07T14:36:19 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
41 / 100
 1311 ms 524292 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]);
}

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 minVal = INT_MAX, min_loc = -1;
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==par) continue;
        dfsCalc(y, x);
        if(minVal > (int)sets[y].size()) minVal = sets[y].size(), min_loc = y;
    }

    sets[x] = sets[min_loc];
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==par || y==min_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);
    }

    /// propagate to childs
    for(auto &chd: centroidChild[c]){
        findAnswer(chd, 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(min(x, y), max(x, y), i));
    }

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

Compilation message

sending.cpp: In function 'int main()':
sending.cpp:198:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  198 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
sending.cpp:200:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  200 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:210:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  210 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct
20 Correct 29 ms 26752 KB Output is correct
21 Correct 39 ms 27128 KB Output is correct
22 Correct 271 ms 73372 KB Output is correct
23 Correct 297 ms 75000 KB Output is correct
24 Correct 234 ms 26920 KB Output is correct
25 Correct 20 ms 26880 KB Output is correct
26 Correct 273 ms 73336 KB Output is correct
27 Correct 25 ms 26752 KB Output is correct
28 Correct 29 ms 26872 KB Output is correct
29 Correct 135 ms 77504 KB Output is correct
30 Correct 359 ms 97604 KB Output is correct
31 Correct 226 ms 72724 KB Output is correct
32 Correct 252 ms 68600 KB Output is correct
33 Correct 84 ms 31592 KB Output is correct

Subtask #3
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct
20 Correct 29 ms 26752 KB Output is correct
21 Correct 39 ms 27128 KB Output is correct
22 Correct 271 ms 73372 KB Output is correct
23 Correct 297 ms 75000 KB Output is correct
24 Correct 234 ms 26920 KB Output is correct
25 Correct 20 ms 26880 KB Output is correct
26 Correct 273 ms 73336 KB Output is correct
27 Correct 25 ms 26752 KB Output is correct
28 Correct 29 ms 26872 KB Output is correct
29 Correct 135 ms 77504 KB Output is correct
30 Correct 359 ms 97604 KB Output is correct
31 Correct 226 ms 72724 KB Output is correct
32 Correct 252 ms 68600 KB Output is correct
33 Correct 84 ms 31592 KB Output is correct
34 Correct 439 ms 48240 KB Output is correct
35 Incorrect 532 ms 48712 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct
20 Correct 29 ms 26752 KB Output is correct
21 Correct 39 ms 27128 KB Output is correct
22 Correct 271 ms 73372 KB Output is correct
23 Correct 297 ms 75000 KB Output is correct
24 Correct 234 ms 26920 KB Output is correct
25 Correct 20 ms 26880 KB Output is correct
26 Correct 273 ms 73336 KB Output is correct
27 Correct 25 ms 26752 KB Output is correct
28 Correct 29 ms 26872 KB Output is correct
29 Correct 135 ms 77504 KB Output is correct
30 Correct 359 ms 97604 KB Output is correct
31 Correct 226 ms 72724 KB Output is correct
32 Correct 252 ms 68600 KB Output is correct
33 Correct 84 ms 31592 KB Output is correct
34 Correct 439 ms 48240 KB Output is correct
35 Incorrect 532 ms 48712 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 516 ms 57748 KB Output is correct
2 Correct 1311 ms 61872 KB Output is correct
3 Incorrect 1150 ms 61696 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #6
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 657 ms 53996 KB Output is correct
2 Correct 985 ms 55888 KB Output is correct
3 Runtime error 768 ms 524292 KB Execution killed with signal 9
4 Halted 0 ms 0 KB -

Subtask #7
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct
20 Correct 29 ms 26752 KB Output is correct
21 Correct 39 ms 27128 KB Output is correct
22 Correct 271 ms 73372 KB Output is correct
23 Correct 297 ms 75000 KB Output is correct
24 Correct 234 ms 26920 KB Output is correct
25 Correct 20 ms 26880 KB Output is correct
26 Correct 273 ms 73336 KB Output is correct
27 Correct 25 ms 26752 KB Output is correct
28 Correct 29 ms 26872 KB Output is correct
29 Correct 135 ms 77504 KB Output is correct
30 Correct 359 ms 97604 KB Output is correct
31 Correct 226 ms 72724 KB Output is correct
32 Correct 252 ms 68600 KB Output is correct
33 Correct 84 ms 31592 KB Output is correct
34 Correct 439 ms 48240 KB Output is correct
35 Incorrect 532 ms 48712 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 18 ms 25600 KB Output is correct
3 Correct 19 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 19 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 18 ms 25856 KB Output is correct
10 Correct 17 ms 25600 KB Output is correct
11 Correct 17 ms 25600 KB Output is correct
12 Correct 18 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 20 ms 25728 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 17 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 18 ms 25728 KB Output is correct
19 Correct 18 ms 25728 KB Output is correct
20 Correct 29 ms 26752 KB Output is correct
21 Correct 39 ms 27128 KB Output is correct
22 Correct 271 ms 73372 KB Output is correct
23 Correct 297 ms 75000 KB Output is correct
24 Correct 234 ms 26920 KB Output is correct
25 Correct 20 ms 26880 KB Output is correct
26 Correct 273 ms 73336 KB Output is correct
27 Correct 25 ms 26752 KB Output is correct
28 Correct 29 ms 26872 KB Output is correct
29 Correct 135 ms 77504 KB Output is correct
30 Correct 359 ms 97604 KB Output is correct
31 Correct 226 ms 72724 KB Output is correct
32 Correct 252 ms 68600 KB Output is correct
33 Correct 84 ms 31592 KB Output is correct
34 Correct 439 ms 48240 KB Output is correct
35 Incorrect 532 ms 48712 KB Output isn't correct
36 Halted 0 ms 0 KB -