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답안 #293044

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
293044 2020-09-07T15:47:13 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
53 / 100
 5000 ms 63724 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]);

    int ret = INT_MAX;
    for(int i=x; i<=y; i++) ret = min(ret, depth[inIdx[i]]);
    return ret;
}

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; 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 LCAdepth(int, int)':
sending.cpp:87:9: warning: unused variable 'd' [-Wunused-variable]
   87 |     int d = cover[y-x];
      |         ^
sending.cpp: In function 'int main()':
sending.cpp:204:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  204 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
sending.cpp:207:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  207 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:217:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  217 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 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 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 45 ms 26744 KB Output is correct
21 Correct 49 ms 26744 KB Output is correct
22 Correct 32 ms 27136 KB Output is correct
23 Correct 32 ms 27000 KB Output is correct
24 Correct 32 ms 26880 KB Output is correct
25 Correct 22 ms 26880 KB Output is correct
26 Correct 30 ms 27008 KB Output is correct
27 Correct 26 ms 26624 KB Output is correct
28 Correct 40 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 27008 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 32 ms 27008 KB Output is correct
33 Correct 30 ms 27008 KB Output is correct

Subtask #3
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 45 ms 26744 KB Output is correct
21 Correct 49 ms 26744 KB Output is correct
22 Correct 32 ms 27136 KB Output is correct
23 Correct 32 ms 27000 KB Output is correct
24 Correct 32 ms 26880 KB Output is correct
25 Correct 22 ms 26880 KB Output is correct
26 Correct 30 ms 27008 KB Output is correct
27 Correct 26 ms 26624 KB Output is correct
28 Correct 40 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 27008 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 32 ms 27008 KB Output is correct
33 Correct 30 ms 27008 KB Output is correct
34 Correct 1101 ms 48996 KB Output is correct
35 Incorrect 1234 ms 49096 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 45 ms 26744 KB Output is correct
21 Correct 49 ms 26744 KB Output is correct
22 Correct 32 ms 27136 KB Output is correct
23 Correct 32 ms 27000 KB Output is correct
24 Correct 32 ms 26880 KB Output is correct
25 Correct 22 ms 26880 KB Output is correct
26 Correct 30 ms 27008 KB Output is correct
27 Correct 26 ms 26624 KB Output is correct
28 Correct 40 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 27008 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 32 ms 27008 KB Output is correct
33 Correct 30 ms 27008 KB Output is correct
34 Correct 1101 ms 48996 KB Output is correct
35 Incorrect 1234 ms 49096 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2595 ms 54344 KB Output is correct
2 Execution timed out 5060 ms 52984 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #6
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1408 ms 53672 KB Output is correct
2 Correct 1831 ms 53400 KB Output is correct
3 Correct 780 ms 63084 KB Output is correct
4 Correct 733 ms 62576 KB Output is correct
5 Correct 809 ms 58352 KB Output is correct
6 Correct 97 ms 55020 KB Output is correct
7 Correct 771 ms 63140 KB Output is correct
8 Correct 171 ms 51832 KB Output is correct
9 Correct 324 ms 50948 KB Output is correct
10 Correct 322 ms 63216 KB Output is correct
11 Correct 507 ms 63724 KB Output is correct
12 Correct 477 ms 63724 KB Output is correct
13 Correct 830 ms 63088 KB Output is correct

Subtask #7
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 45 ms 26744 KB Output is correct
21 Correct 49 ms 26744 KB Output is correct
22 Correct 32 ms 27136 KB Output is correct
23 Correct 32 ms 27000 KB Output is correct
24 Correct 32 ms 26880 KB Output is correct
25 Correct 22 ms 26880 KB Output is correct
26 Correct 30 ms 27008 KB Output is correct
27 Correct 26 ms 26624 KB Output is correct
28 Correct 40 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 27008 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 32 ms 27008 KB Output is correct
33 Correct 30 ms 27008 KB Output is correct
34 Correct 1101 ms 48996 KB Output is correct
35 Incorrect 1234 ms 49096 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 21 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 17 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 20 ms 25600 KB Output is correct
9 Correct 18 ms 25632 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25600 KB Output is correct
13 Correct 20 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 25600 KB Output is correct
19 Correct 18 ms 25600 KB Output is correct
20 Correct 45 ms 26744 KB Output is correct
21 Correct 49 ms 26744 KB Output is correct
22 Correct 32 ms 27136 KB Output is correct
23 Correct 32 ms 27000 KB Output is correct
24 Correct 32 ms 26880 KB Output is correct
25 Correct 22 ms 26880 KB Output is correct
26 Correct 30 ms 27008 KB Output is correct
27 Correct 26 ms 26624 KB Output is correct
28 Correct 40 ms 26744 KB Output is correct
29 Correct 25 ms 26880 KB Output is correct
30 Correct 29 ms 27008 KB Output is correct
31 Correct 27 ms 27008 KB Output is correct
32 Correct 32 ms 27008 KB Output is correct
33 Correct 30 ms 27008 KB Output is correct
34 Correct 1101 ms 48996 KB Output is correct
35 Incorrect 1234 ms 49096 KB Output isn't correct
36 Halted 0 ms 0 KB -